Twice for me.
First time i accidently pushed the panic button in work.
Armed police where there minutes later. Went to the shop door to see what all the commotion outside was, and there was the fuzz with their weapons drawn and pointed at me.
Second time was in this bar
http://www.toytowngermany.com/munich/paddys_irish_pub.html.
I was sat at the bar when a guy walks in and pulls out a gun points it at us and says he's looking for someone.
The barman said he hadn't been in that day and your man left.
Funny thing was that he didn't go very far, we could see him standing outside waiting. The barman called the cops who promptly arrived and apprehended the gentleman.