I've just gotten used to carrying my helmet with me if I'm on my sportster or my TU250. If I'm on the Wee I lock it in the top box. I had a friend who had his helmet messed with when he had it locked on his bike. Somebody dumped a coke in his helmet and smeared ketchup in it. I guess I'm in the out of sight out of mind camp. I'm too paranoid to leave my helmet out in the open.