mh why you bothering about this? Crime is a part of life and it is down to the individual to make sure his/her bike is locked up securely with a decent lock. I'm assuming the lock used to lock the bike was weak hence the thief's easily cut through it. If the bike owner was really concerned about theft then he/she should have bought a proper lock that would at least deter any would be thief to think again. It is the bike owners responsibility to make sure his/her bike is locked up securely not yours so don't worry about it. I see many bikes locked up poorly with a cheap lock and just don't understand why people do it. Maybe its because they can't be bothered to buy a decent good quality lock. Also, Tesco should really improve there bike racks because the one's I've seen down my local Tesco are absolutely s**t!
Jamesup yes I don't deny that with the right tools and enough time the thief could get through any lock but I was just trying to say that maybe the bike owner should have got a tougher lock. Mh did mention that the teenagers got through the lock so easily so this gives me an impression that the lock used was weak and probably cheap too. It's a bit like buying a cheap lock for your front door and then expecting someone else to notice the burglary if it happens. Would one not buy the best lock for there front door so that the burglary didn't happen in the first instance?
Anyway, I am glad mh made all that effort to try and help and there should be more people like mh and then the world would be a much safer place. But the responsibility should not lie entirely with the members of the public to keep watch and the owner should take some responsibility too IMO.