Freecycle: Claim these frames

So is the removal of bikes ok if you have permission from the private land owners? (in this case Sainsburys) I remember reading the abandoned bikes thread a while back

http://www.lfgss.com/thread404-6.html

Gaining the permission of anyone to re-appropriate ownership or property which is not theirs to give away is called theft (Even if you do earn gutter rent working as an "honest barman" in one of this cities fine establishments).
(not my belief or opinion, just remember reading this and it sounding serious]