Family members "should not be bidding on each other's listings." See "Shill Bidding" on this page:
Lee Berg Palo Alto
Mark Chandler wrote:
> It's part of the policy. I just put several items on eBay last night
> and this morning (Bridgestone catalogues), and in the confirmation
> e-mail, it said that "shill" bids were against eBay's policies. Now,
> whether they consider this to be a shill bid may be up in the air.