Yes Flecc/Mussells; cynicism is a useful tool when operating on ebay. Fortunately, one can ask questions and make judgements accordingly.
There is an excellent dispute procedure in place via ebay and Paypal, where applicable, much better than exists with any street market or newspaper advert. Anybody wishing to chance their arm in ANY auction needs to have their wits about them and ebay is an auction site. The age-old adage should be foremost in the minds of potential buyers, "Let the buyer beware!".
That said, I have bought two bikes that way, both fantastic machines and I'm delighted at my good fortune. For those lacking confidence, either don't play or if you really want to, try cash on collection deals and take a large mate or two along to the pick-up point.
There are bargains to be had!
Indalo