Yes - I have, and it was when I was looking hard for a 1D MkII/IIn body when dealers were asking around £2,000 for the IIn. The very well priced MkII apparently was in Birmingham, not too far from where I live in Milton Keynes, and initially the seller seemed to be asking quite legitimate questions about how I would pay etc. I did wonder if it was stolen. Equally, I was concerned about what state the goods were in, and how safe I might be carrying large sums of cash. The emails gradually got more bizarre, how genuine was I?, new place for handover etc. (now moved to somewhere in London, always where seller required) and I decided that my peace of mind would be better if I let matters drop. Shortly before I dropped out, I wasn't even sure that the item existed.
I was a bit surprised that I got no threatening follow-up emails - as though the other guy had ceased to exist...
Interestingly, around the same time my phone call to a well known UK seller advertising a s/h 1D MkIIn never got taken up. I was about 5 miles from his base, credit card half way out of its holder, and was checking how to find his outlet. When he answered my call he said he was away from base, and that his staff were too busy packing and despatching items for the 2006 Xmas, and never phoned me back - of course my number should have been recorded on his mobile. The 1D MkIIn was easily his highest priced item, and I wondered if it was a "virtual item" on his website for nothing more than giving "legitimacy" to his site.
For the record, I bought a 1D MkIII from a dealer recommended here last Spring (via credit card) and it's been fine.
