Ways not to lock your bike

Was on my way out of Tesco's the other day and saw a bloke with dusty lycra and top-range Sidis shopping, obviously after a long ride. Got outside and as expected his expensive Trek was leaning against the wall well away from the doors unlocked. Three lads walked by and one went to take it but the other two stopped him when they spotted me, I even hung around till he returned to his bike.

That's why one should only shop at Waitrose. Went there the other day, locked my bike and noticeed a Charge ... unlocked. I frowned for a bit, "shall I stay and look after the bike" and decide to go in and see if I can spot the owner. See a guy with a courier bag and ask"do you have a Charge bike?" "eerrr yes?!" "You haven't locked your bike". He ran outside, locked and came back with a big smile. I am pretty sure he could have left it there unlocked for a while without any problems.