I hooked up my computer to my home stereo to show the game off to my roommates. I lived in an apartment in a bad neighborhood at the time.
I started to play and got as far as two shotgun blasts in before pressing pause to answer the phone. Shortly after the phone rang there was a very loud and forceful knock at the door. Said knock was followed by 'open up, police!'.
I went to the door, confused why the police were banging on my door. Several officers were standing outside with their guns in their hands while I had my phone in my hand. In my confusion I asked them what they wanted. They said they had reports of shots being fired and demanded entrance to my apartment. I let them in and showed them my computer with the game still paused. They were incredulous and didn't believe me, searching the apartment instead.
Ten seconds later they came back after finding nothing of interest. They then let me show them the computer game. I then showed them that by clicking the keyboard I could make the shotgun noise they heard.
Many additional police vehicles were outside. The officers had not yet bothered to tell the many additional cops outside that the shotgun was just a videogame. Much panic ensued as the officers outside started to yell 'shots fired' with their fellow officers inside my apartment..
Moral of the story. Make sure the officers communicate to each other. Amazingly when all was said and done I got off with a warning (since it was before 10pm) and many policeman looking at how I hooked the computer into the stereo.