My colleagues (in the gun-estranged society of Denmark where no one owns weapons) were in disbelief when I told them about deadly 4th of july accidents caused by firing guns into the air.
In America of course they have to actually legislate about it:

In crowded cities, however, the probability rises dramatically, and people get killed quite often by stray bullets. Most major cities have laws in place to try to keep people from shooting guns into the air in celebration

Further notes, with numbers