So let's talk locks and security

First of all, the bike, to the untrained eye (opportunist thieves), looks improperly secured. A very well secured normally is obvious, even from across the street, because the lock goes through at least a wheel AND a major part of the frame. Since the Sheldon Method does not secure the frame, then the vulverable part is the wheel. Rims cannot possibly be as strong of the solid steel section of a u-lock, especially a good u-lock.

To comprehensively defeat the Sheldon Method, all one needs to do is this:

1. Deflate the tyre
   
2. Use a sharpened bolt-cutter to cut through the rim (and maybe a couple spokes).
   
3. Use an extra sharp knife on the tyre, as the bolt-cutter may get stuck on rubber.
   
4. Leave behind mangled rear wheel and tyre, with an undisturbed lock.
   
   
   

Theft want to able to sell the bike, the last thing they want is to sell a bike without a back wheel, front wheel are easy to replace but back wheels less so.

Yes, I have appeared to give away advice to thieves

Don't assumed that thieves are stupid, that's the first mistake cyclists made when locking their bike.