I was recently cleaning a house when the neighbour next door asked me if I was going to clean his windows. I said I'd be round when I was done here.
Went round, gave him a price. He said he'd better check with the wife. He came out and said they already had a window cleaner, and he charged £3 less than I quoted him, but could I do it for this same price. I declined, as I didn't realize they already had a windy, and didn't want to take his work.
As it turned out, I know his windy. He's a nice bloke, doesn't charge enough really, but has given me work for free in the past which has turned out to be very good work which is well priced, so I would never do the dirty on him.
John.