I have done this on occassion for a quick sale - it is not a case of putting my bid price up to the BIN price but the other way round. It encourages those that prefer to BIN and most of the time the items I was selling that way wouldn't have gone for more (and I wasn't willing to take less). so you see, it all depends on why you do this... also the tax law here in germany will not allow me to just go for the BIN option (or is that ebay?) - you have to be a merchant trader and pay taxes on your purchases.
anyways, get this: I have just done that for an item but someone actually bid rather than BINed. I tried to understand why, and the only thing I can think of is that they don't have the funds to pay yet, so waiting for the auction to end - maybe then use their new pay cheque???