"officers must have tangible evidence or an admission from the victim before marking a case as unfounded."

So unless the complainant confesses to public mischief or the police have evidence the crime didn't happen it goes ahead (unless of course the crown has a say and the Chief is "forgetting" to mention it). This is a lower standard than other crimes where the police need evidence the crime was committed to lay charges. 

For example if A. complained he'd been punched in the stomach by B. a year ago. B says it never happened. There was only A's word for it and no other direct or circumstantial evidence. Would it go to court? If it did would a conviction be likely? Is there something else the police and prosecutors could be doing with their time other than losing trials?