Security shoud take a "layered" approach. The steering lock, a chain and padlock, a cutoff switch, leaving the bike in your sight, all are defeatable but in combination, they slow the crook down and make him decide if it's worth it.
When I go to Walmart, I always park my 919 in the yellow stripe area right up near the big crosswalk leading through the front doors. People walk past it right and left. I leave my jacket, helmet, and gloves on the bike. The deterent is that if someone took them, they'd have to do it in front of all the people going in and out of the store. Someday someone will take them, I know, but the concept is to make the thief decide if the risk is worth it.