If you use Namejet’s auction system you (should) know that your prebid is not a proxy bid system, it is a bid system. This means if you prebid $1,000 and there is no one else bidding you will wind up winning the domain for $1,000 instead of $69. Someone on Namejet bid $1,501 on the domain name MichaelBlack.com. There is only one bidder for this domain so this (un)lucky person is going to overpay by about $1,430. If this is you then get in there and change your bid to $69 ASAP.
If you bid on Namejet, my advice to you is never put any more than $69 for your prebid. I don’t know of any benefit to bidding more at the start, and as in the above example you can see that it is going to hurt someone to the tune of some big bucks.