I'm not sure this is that big a deal considering the default Windows representation of the pistol emoji has always been a toy gun rather than a realistic depiction of a firearm. It looks more like a ray-gun to me rather than a water pistol, so you're unlikely to say "we should [ray-gun] John after school", but there's clearly opportunity for misinterpretation if you're trying to communicate with these symbols.

But I would have thought the obvious solution was to avoid using emoji as a form of communication. They're always going to vary from one platform to the next, so you never really know exactly what the recipient is going to see.