I have never had a bicycle stolen from me. Some luck, some paranoia. An idiot tried to steel a mtb from me once while I was occupied shopping in a walmart. He had poor timing. I came out of the store in time to see him wheeling it toward his pickup. I rammed him with the Super walmart shopping cart several times against his pickup. I also twisted him to the ground via his hair and jaw. I put my groceries in my panniers with my bicycle leaned against his pickup. I waited for the police and ems, he had warrants and I have impulse control issues. My bicycle is 5' from me in my bedroom as I type this.