Whether you allow a person to cancel a bid is up to you, however, if you allow a bid to be canceled, you have to distract all the bids from that person from the auctioning so it won't be unfair to other bidders.I would have to agree with her on that one. Sometimes they are one of the only people planning on bidding and/or there's no one else willing to go that high with it.
Oh, and I was also curious. I'm supposing you meant "detract" rather than "distract"? I could be wrong...
Edit: Other than that I really would have to say that it's nice to see this sort of thing up. It's a nice thing to go by, and I know I've seen it asked for at least once or twice now.