Personally, I am not so sure with the amount of people who are "accidentally", or even intentionally shot in places with "get away with murder" laws that this might be a grammatical error. People are accidentally shot while hiking on trails: the Appalachian Trail even gives a warning to hikers to wear orange in hunting season to try to avoid hikers being shot.Take this sign:
It might not be too far off to suggest the first sign WASN'T a grammatical error when people walk around armed in inappropriate situations. Additionally, shootings are given a slap on the wrist, if even punished.
As the song goes: "Yanks with guns, say shooting people, is such fun".
