I've seen this happen a lot in the past, and it was obvious what was happening but buyers in our group didn't care. The companies that did this would start an item at a very low price, then near the end bid it up to about $90. These were items that would normally sell for around $100 so it didn't matter to us, we could still buy the items at better prices than anywhere else. All the sellers did was to reduce their listing fees and insure that one of their items didn't accidentally go for a lower than market price.
If a seller is using shill bidding to bid items up to prices that are too high then just consider that this seller doesn't exist and ignore their auctions.