Sometimes it goes wrong. Many years ago, about 2 a.m., working Brussels Upper Airspace (FL195+) the lower Sector advised me that a dep off RWY 24 would come straight to me , "released" A DC8 called me, "rolling" and was cleared , "When convenient, direct DIK; no ATC speed restriction." This put him directly over the city about 2000ft and accelerating. Apparently the airport switchboard did a Christmas tree impression for several hours!!. Next morning I was requested to remain for a no coffee, no biscuits discussion. Funnily enough we never got anybody that early on the frequency again and the conditions of a traffic release were changed soon after
