Your relationship to the person on whom you are spying matters. If that person is your child or your employee, you have a lot more leeway when it comes to monitoring their activities. If you think someone is spying on you illegally, file a report with local law enforcement so they can investigate your case.
Most cats snooze around 16 hours per day. The majority of their sleep time, however, is much shorter than the typical seven hours or so that humans average at. night. Cats tend to sleep lightly, without going into a deep sleep.
Cats sleep a lot and it is perfectly normal. In fact an average house cat will sleep the majority of its life away. It's one of their most favorite activities and they are really good at it. Most cats will sleep about 16 hours a day, and some even more than that.