I think Mearls hit the nail on the head. If there's no subversion of the mechanical boundaries going on there's no reason to force someone to use their short-bow or dagger to get their Sneak Attack when it would be much more germane to the scene to be throwing a hatchet, a chamber pot, a brick, or a beer stein at the back of someone's head. As long as you're not getting a mechanical advantage out of it (typically more damage) there's no reason to call "foul."
Marty Lund
Marty Lund