One factor that can come into effect is that 
within Rinkya's system, Rinkya users are 
(oddly enough) also bidding against each 
other. 

To me, seeing Vhd_link means, "Oh crap, 
potentially more than one pesron wants this 
item"... but , a bid war is a bid war.

Granted, if deputy services didn't exist, bids 
might dramitically diminish; winning bid  
prices would be lower; and a selective Otaku 
that love to feed their hobby of securing 
Japanese goodies might have to solely resort 
to monthly / yearly (AX) convention finds. 

If you're using a deputy service and bid more 
than you can pay, undoubtedly things would 
get VERY ugly. And since most Yahoo! Japan 
auctions are 'sniper' protected (bids after the 5 
minute mark will reset to an additional 5 
minutes to allow for a rebutal), the arguement 
that, "I didn't get a chance to bid on the item." 
doesn't hold.

The bottom line is, if you have the 'auction' 
money to pay / bid for an item you'll do so 
(imo).

Perhaps the "heyday" (less competition) on YJ 
bidding has come to an end...::sigh::...