I've always been too paranoid to leave my helmet with my motorcycle when I park it, but I always see other riders doing this. Most of them don't even lock it to the bike.
Considering all the hoodlums and numbskulls out there, I'm surprised their helmets don't either get stolen or knocked off the bike onto the ground.
...yes, I think very lowly of how the human race conducts themselves in parking lots. Don't even get me started on gotdamnned door dings....
For those of you who leave your helmet with your bike, how long have you been doing this, and has anything ever happened to your helmet?