I would disagree about making an open bid on eBay. Placing a bid signals interest and that seems to attract bids from others. The point of AS is to conceal interest until the very end.
I have encountered a handful of auctions that ended early, but with literally millions of auctions going on at any moment, I think you will find that only the tiniest percentage are ever ended early. I would definitely say that it does not happen with the frequency that "alot" suggests.