I don't know about Canadian law, but here in the US, most states do have laws that something along the lines that you need to produce ID if a law enforcement official asks you too. So if this person didn't show ID then there is a legal issue involved if that is also the law up in Canada. As for why he was asked to show ID that could be for a variety of reason. Was there a function happening where he was? Was he just walking by, or wandering repeatedly around the perimeter? Had someone there seen him wandering around and called the police? Had there been a rash of robberies in the area recently upping the suspicion factor for the officer? If he was just walking by it was probably a bit much, but if the officer thought he was acting suspiciously then checking his ID isn't necessarily uncalled for.