Interesting idea, but it really only seems slightly better than not locking it at all. Carrying a lock when I need to use it is a very minor inconvenience to me, especially when compared to worrying about it even for a few minutes.

At my college there are a few other bikes I see in the rack fairly regularly, one or two just lock the front wheel, the other one or two sometimes lock the front wheel and through the main part of the frame. All of these bike have quick release wheels/seats etc. Often helmets, tools and lights are left on them as well. Bike theft isn't all that big around our city, at least it doesn't seem to be. I'd feel bad if something happened to one of their bikes, but they make mine look like an armored tank, hopefully also making mine less of a target. I don't leave anything on it, and it's U-locked with a thick cable catching more of the bike rack and the front wheel and running back to the U-lock.