Image copyright Changzhou First International Trade Image caption The Chinese firm calls its vehicles "surfing electric scooters" 
 
 US marshals have raided a Chinese hoverboard-maker's stand at the CES tech show in Las Vegas. 
 
 The officials confiscated all the company's one-wheeled vehicles and took down its signs after a Silicon Valley-based rival filed a patent infringement claim. 
 
 The case is set to return to court in a week's time. 
 
 The Chinese firm, Changzhou First International Trade, told the BBC it did not believe it had broken the law. 
 
 It claimed it had developed its hoverboard a long time ago and had hidden it until now to avoid it being copied by other Chinese firms. It added that this was the first time it had been involved in such an incident. 
 
 A spokeswoman for the US Department of Justice told the BBC: "A court order has been served in a civil case involving private litigation." 
 
 She added that while it was not uncommon for the US marshals to be involved in such action, she could not recall another case happening at a trade show. 
 
 Media playback is unsupported on your device Media caption Click's Spencer Kelly took a ride on a Onewheel in 2014 
 
 Footage of the incident has been posted online by the news agency Bloomberg. 
 
 Restraining order 
 
 While there are many companies exhibiting hoverboards at CES, the Chinese firm's models - which it calls Surfing Electric Scooters - were unusual for having a single central wheel rather than one at each end. 
 
 This is similar to California-based Future Motion's Onewheel vehicle, which uses sensors and computer controls to keep the board balanced. 
 
 Image copyright US Patents Office Image caption A design patent for Future Motion's design was issued on Tuesday 
 
 "We have design and utility patents that cover our invention," Future Motion's founder Kyle Doerksen told the BBC. 
 
 "When we got word that a company was exhibiting a knock-off product, we engaged in the formal process, which involved sending a cease and desist letter and then getting a restraining order, which was then enforced by the US marshals. 
 
 "As a company that launched ourselves at CES two years ago, we know that the world is watching. 
 
 "And we knew that this was a situation where they could do real damage to our business if we just allowed them to violate our patents." 
 
 Changzhou currently lists its device for $550 (£375) on the Alibaba shopping site, which is about a third of the price of the Onewheel. 
 
 Image copyright Future Motion Image caption Future Motion alleges that its designs have been illegally copied 
 
 There are two patents involved in the case: 
 
 One for the design of the Onewheel vehicle, which was only issued earlier this month 
 
 The other, setting out methods to make the skateboard self-stabilising, which was filed in April 2014 
 
 "Punitive measures could include a permanent injunction preventing Changzhou from selling the product in the US, monetary damages including lost profits we can prove due to infringing sales, and even attorney's fees if the court decides it's an exceptionally egregious case of wilful patent infringement," said Future Motion's lawyer Shawn Kolitch. 
 
 He added that Future Motion had patents pending elsewhere including in China, which it hoped to obtain in order to stop Changzhou manufacturing the device. 
 
 Image copyright Alibaba Image caption Changzhou advertises its CES appearance on its Alibaba listing, which says it can ship them worldwide 
 
 Safety risks 
 
 This is not the first controversy hoverboards have faced at CES. 
 
 Ahead of the event starting, its organiser announced that attendees were banned from using any type of the vehicles to get about its showfloors. 
 
 Dozens of universities and other institutions in the US had earlier banned their use and most of the country's airlines have also refused to carry them. 
 
 The problem is two-fold. 
 
 They have been involved in incidents where people have been injured or killed when the rider lost control. 
 
 And some of the gadgets have burst into flames as a result of problems with their batteries, leading to concerns that some manufacturers are not following safety standards. 
 
 Read and watch more from CES and follow the BBC team covering the event on Twitter. ||||| (CNN) "Back to the Future" Day is Wednesday, and fans are tallying up the 1989 film's predictions of life in the year 2015. 
 
 How did the movie do? Here are some of its hits and misses: 
 
 Big-screen televisions and video conferencing: Yes 
 
 The film features several scenes of characters watching screens very much like the oversize ones we actually use these days. That's saying something, because most TVs of the 1980s were heavy, square appliances with bulky picture tubes. Some of them even came in wood-grain cabinets like furniture! 
 
 Also, the "BTTF II" characters talk to the screens just like we do today. Not bad, given that videophones -- though long promised -- barely existed in 1989. 
 
 Hoverboard: No 
 
 Despite the recent Lexus commercial showing skateboard aces skimming around a skatepark on maglev hoverboards, the technology just isn't there yet. The Lexus hoverboard requires a special surface to ride on, as does a rival, the Hendo. 
 
 Another hoverboard, the Omni, is essentially a skateboard with helicopter rotors. Sorry, we'll just have to wait a little longer before flying around Hill Valley is commonplace. 
 
 News drones: Yes 
 
 During a crucial scene in the film, a USA Today drone can be flying around the Hill Valley courthouse taking pictures. Major media companies, including CNN, are now looking into using the tech for news purposes 
 
 Hands-free video games: Yes 
 
 Our intrepid time traveler, Marty McFly, plays an arcade game called "Wild Gunman" at Café 80's in 2015. Two kids are shocked that McFly has to use his hands to play, calling it a "baby's game." Thanks to products like Xbox Kinect, hands-free video games are now pretty commonplace. 
 
 Fashion: Mixed 
 
 The less said about the custom of wearing two ties at the same time , the better. However, the movie did get the concept of everyday athletic apparel right. 
 
 Everyday consumer products: Yes, with an asterisk 
 
 Pepsi is still around, and the beverage company wasn't going to miss a chance to put out a limited-edition Pepsi Perfect like the one Marty orders in the film. But the key words are "limited edition." Similarly, in reality, "Jaws" only made it to "Jaws: The Revenge" (the fourth film in the series), but that didn't stop Universal from putting out a fake trailer for "BTTF II's" "Jaws 19." 
 
 But there's a Pizza Hut in town, and the McFly family is shown chowing down on a pie. Some things never go out of style. 
 
 Video glasses: Yes 
 
 Marty McFly's troublesome kids wear high-tech goggles to the dinner table, which are remarkably similar in function to Google Glass, Oculus Rift and Samsung VR. 
 
 The World Champion Chicago Cubs: ?
– Hoverboards are making headlines, from bursting into flames and being banned by online retailers to causing trouble in churches and supermarkets. But the hoverboard hubbub at CES in Las Vegas Thursday was something straight out of a corporate espionage movie: Per Bloomberg, US marshals raided a booth set up by Chinese company Changzhou First International Trade. It was promoting its Trotter electronic skateboard—what Bloomberg describes as looking "like a seesaw with one big wheel in the middle." The problem: Silicon Valley startup Future Motion says the product is a knockoff of its own Onewheel skateboard, invented and designed by Kyle Doerksen. "When we got word that a company was exhibiting a knock-off product, we engaged in the formal process, which involved sending a cease and desist letter and ... getting a restraining order ... then enforced by the US marshals," Doerksen tells the BBC. The marshals who swept into the booth scooped up a Trotter, plus marketing material. A quick visual comparison of Future Motion's product and those hawked by Changzhou on Alibaba does show a marked similarity. But while Future Motion sells its version for $1,500, the knockoffs are going for around $550 each—which Doerksen says is bad news for not only his company, but the hoverboard/electric skateboard industry overall. "If customers start to view the space as full of low-quality, low-cost products, that reflects poorly on everybody," he tells Bloomberg. Future Motion, which the business site notes started the patent process for parts of its Onewheel years ago, didn't set up a booth at the consumer electronics forum this year, but Doerksen was in town meeting with possible partners. (Even Wiz Khalifa has had hoverboard issues.)