I do not think they were accusing you of shill 
bidding.  I believe their concern is that this 
new bidder is bidding irresponsibly with no 
intention of paying, and is therefore just 
jacking up the price. At least, this is a 
hesitation that always runs through my mind when 
I see a new bidder bidding on something I am 
interested in.  Given that there ARE people out 
there who seem to think it's fun to bid on ebay 
auctions just to make everyone pay more, I guess 
I can understand their concern.