On its own its a dumb idea, but I do think another commenter had it on the money how this is more a ploy to catch trump with his pants down. Trump can either agree and piss off his pro gun base (and look like a coward given his previous statements), he can argue against it and seem like hes inviting more violence and alienate anyone in his base who thinks gun violence is bad. Or he can ignore it and look like hes a doddering old fool oblivious to whats happening around him.