I've noticed that when I bid against a Celga 
(doujin_box) bidder, more often that not they 
have put in extremely high "nuke bids".

I believe that this is because they don't have 
good control over the timing of the bids, and 
don't necessarily have an opportunity to re-bid, 
and will lose any opportunity to re-bid if their 
first bid gets topped and there is another Celga 
bid waiting in line.  So I believe that in 
response to this, some Celga bidders place 
extremely high "nuke bids" to try to lock the 
item down.

When I see doujin_box bidding on an auction, my 
heart really sinks...