I was at the climbing gym and couldn't find a locker. The bag I wanted to stow is ancient and my street shoes are cheap so I wasn't worried about losing them. The worst that would happen is that I'd have to bike home in my climbing shoes and use one of the new, nicer messenger bags I've bought but never get around to using. I just didn't want to lose my brand new bike helmet, though any thief that would take it would have to be pretty damn sure karma does not exist. So I took my lock and ran in through the vents in my helmet. Someone might still be able to take it, but it'll be pretty uncomfortable with my lock digging into their skull.