I’d suggest that there’s an even greater potential for over-reporting if the criteria used to be “4 dead, not including the shooter” and seems to have evolved to “3 dead, and shooter may be included.” Under the more “inclusive” standard, a gunman need only kill two others and then shoot himself or be shot by cops / armed Good Samaritans. That seems pretty different from “a bad guy killed 4 or more people”.
I understand that the FBI report being discussed may provide a better filter - I’m just concerned at the methodology for counting and reporting “mass shootings” to the masses.