What were you thinking, O bicyclist? Through the wheel, not through the frame, quick-release on the same wheel! This was so easy I almost stole the bike myself (but would have given it to the guard of the nearby building, I swear).
Maybe this individual was trying to reproduce Sheldon Brown's lock strategy?
People tend to buy the big clunky U-locks because they don't know how to use them properly. A U-lock should go around the rear rim and tire, somewhere inside the rear triangle of the frame. There is no need to loop it around the seat tube as well, because the wheel cannot be pulled through the rear triangle.
I guess this is the problem with tricks. If you just learned a trick and try to reproduce it, did you do it right? If it's so tricky, how can you be sure? This is part of why I try to avoid cleverness in general: too high a chance of fooling yourself into thinking you're right.
For the record: I do not use Sheldon's lock strategy.