I also agree with this statement however if it's a item that's rare and I want it bad most likely other people will want it as well and try and get seller to end auction early (which I WON'T do) so I'll throw a large starting bid out there so if seller does end early he'll get dinged the fees in amount of highest bid at time he ended it. At least that's what I was informed would happen last time we disused ending auctions early.
Bingo... 63shelby has it right... thats the best way to prevent sellers from ending early!
You could contact the seller and inform them that you're going to be a strong bidder on this but choose not to bid early. Tell them that if they are tempted by others to end the auction early, send you a message as you will most likely pay more than those that try to get you to end early. Remind them that the whole reason others may try to get them to end early is because they know you will outbid them should the auction run its course.
90% of the time that I don't snipe and bid early with a strong bid I have some nimrod climbing the ladder and bidding 5-10 times on the last day until they either top my bid or make me pay hundreds more than if I sniped.
I'm also thinking a seller that's dumb enough to end early doesn't put that much forethought into the fees.