cyclistm: He did actually. I ordered in another one for him. I fully understood his annoyance, but under sales laws, it wasn't his, he hadn't actually closed the deal, so didn't really have a leg to stand on. It was on the counter, not in his hand. I think the same sort of thing applies with supermarkets etc; if you leave a trolley or basket unattended, and someone else nabs something out of it, it's tough shit. I dunno.
Bad manners at worst, really. But the second bloke was the first to actually hand over money, so legally I think he had formed the 'contract' with the shop. He came back as well, and we had a laugh about it. First bloke was a bit of a ditherer anyway, so maybe he learned something.
I had someone try to have it away with a pair of trainers I was about to buy in Selfridges sale once. I told them not to be silly…