A man in Kaikohe, Northland, New Zealand strode into a convenience store with a machete. He was, of course, up to no good.
So the store manager activated his fog machine.
What, you don't have a fog machine in your home or place of business? This is, apparently, a long-used crime deterrent. Not only does the fog make seeing the loot and victims difficult. It can also coat the robber with traceable chemicals.
I had never heard of this, but now I think I really need one to get out of awkward conversations. For this scenario, a fog machine that hangs on my belt would be ideal. If find myself trapped in a one-sided conversation with someone who won't shut up, I can press the button and escape.
-via Boing Boing
About identifying the perp - cameras would capture their image(s) before the smoke's deployed, but criminals usually hide their faces anyways, so the smoke's not a big factor in identification.