There was a gun show downtown concurrently so he might have just bought one or two of them? Probably stored in his room along with the ammunition. Proceeded to get drunk in the hotel bar and was being belligerent when the mounties were called to escort him out. He became combative and was arrested for his trouble. As mentioned by another poster, the trespass was a milder form of drunk and disorderly, and much kinder than assaulting an officer. They went to his room for personal effects when they discovered he was a guest there and discovered the guns.
I believe we have a winner. Not just plausible, but probable.
Fing fake-news media scum couldn’t tell the truth with a gun to their heads. Which could be why they’re so anti gun: they’re afraid someone will put a gun to their heads and demand they tell the truth.