Used to carry it in our helmet bags if at a mall or store now just use the tour pak.

 

Sports Authority or a local Ski shop will carry a retractable cable lock that is about the size of a pack of cards and has a 36" cable. In winter I use it to lock up the skis while taking a break. Like someone said about the helmet. If your skis get stolen up on the mountain, it is a long walk home. In summer I use it to lock the helmets thru the D Ring.

The locks run around $15.

 

I use a cable type gun lock to lock it to the handle bars when I feel I need to lock it up. Most of the time, though, I just hang it from the brake lever. Never had a problem yet.

 

I have an HD helmet lock on my case guard. It works fine and I can lock up both my wife's helmet and mine with it. Not really worried about someone taking it but someone might knock it off the bike so I lock it up when I am out of sight.