Originally Posted by FTv3

Again, you’re hearing the 100% accurate story.

You can’t “submit” a blank bid but you can hit (inadvertently?) “delete” instead of “submit” and you will get a confirmation number, effectively submitting a blank bid with no indication of what you’ve done. When a delete gets submitted right after a series of valid bids in the last minutes of the window closing, you can easily infer the intentions of the bidder. No one decides not to bid vacation, especially seconds before it closes.