"Error, you cannot print toiletpart.stl because there is no open permit for the the address at which this printer is registered, contact a licensed plumber during normal business hours"
Don't laugh, this sort of regulatory capture type crap is exactly where it'll trickle down to if they get what they want for guns.
Also: "I see you are trying to print a hollow cylinder. Sorry, you can't print gun barrels"
Also: "The Letter_C.stl can't be printed because it is an 88% percent match for a gun trigger"