It is frustrating being out-bid on e-bay, especially by a retro-biker, but at the end of the day if they are willing to pay more for something than you are then why shouldn't they have it?
If I get outbid by someone then fair enough. I think I know what the market value of things are so if somebody wants to pay more, then they are paying over the odds. Thats up to them.
Also, what if you 'warn off' other retro bikers but then get beaten on e-bay by someone else (who isn't a member of this site) that way we've all lost out! There are over 600 users on retrobike whose need for that special part may be just as great as yours, why shouldn't they have a crack at it?
We just need to be nice to each other, be realistic about what things are worth and accept that sometimes you win, sometimes you lose. Thats e-bay, its not a shop, its an auction
If you lose, ask about, you'll be surprised what turns up.
Unknowingly, Sticklegs and I were bidding for a Mavic 316 headset a while back, he won. I then bought a Ritchey Logic instead. It turns out that he would have preferred the Logic so we swapped
By talking to each other we engineered a 'win-win' situation.