People are injured by celebratory fire all the time. That said, getting hit by a stray bullet of any sort is very very rare, which is the reason the stories stick in your head. Children get killed and injured (or injure others) by playing with unsecured guns as well.

The fact is that if there are guns around, there is a little bit of danger especially if they are loaded. Stricter gun laws tend to produce less gun violence and accidents.