It pays to be bright when making bomb threats
Haven't heard much mention of the Darwin Awards lately. This may qualify:-
Imagine a setup where the call centre you run is connected to an Ericsson AXE10 exchange you also own. So callers into the call centre route over lines you manage. Not only manage but have full engineering access to including call tracing - at a level that gives full call details. Then mix in a disgruntled customer who decides to call into their own service provider and issue a bomb threat. But they think they're clever as they withhold their number. The call centre agent presses their malicious call trace key flagging the call. This provides us with the agents extension number and we duly trace the call 'live'. This provides the originating CLI as whilst the caller masks it we can still see it; then we run the number for a laugh into our customer database only to find a match.
So when calling 999 we provide their name and address and the fact they're still Iive on the call.