Questions about the security of buying things on

Hi, all. I intend to buy things on

But I found that there is a problem about the security of ONLINE auction.
For example, if A want to sell out something for a high price on,
he/she can register a number of different accounts, pretend to buy the item
on the behalf of different usernames that he/she wants to sell and raise up
the price that he/she set by oneself. In this way, he/she can cheat the real
vendees and sell out his item for highest price.

Maybe this kind of circumstance could happen in the real auction activities,
but I think it is more likely to happen in the online auction deals
especially when the item is popular online. Is that true?

Is there any merchanism to avoid the fraud on Or should they set
up one to avoid that?

Look forward to your opinions! Thanks very much.