The guy is probably lucky it was an airsoft gun, which is likely lighter than the real thing. I can only assume it had the requisite orange tip, so the customer who grabbed it knew full well it was airsoft, and not a working firearm.
CLEVELAND, Ohio -- A Cleveland man used an airsoft gun to threaten Taco Bell customers, who then took it from him and pistol-whipped him at the restaurant near Public Square, police said.
http://www.cleveland.com/crime/2019/02/customers-grab-gun-from-angry-cleveland-man-at-taco-bell-then-beat-him-with-it-police-say.html

What is the point of rules that are not enforced?