E-bay won't ever do that.

1: They don't want buyers to get "huffy" and decide to play somewhere else. After all they might actually really buy something one day.

2: It will give sellers a reason to start cancelling bids and bbl the suspect buyer. Which may might slow down auction increases and lower fees.

3: Occasionally sellers might not go through the NPB system and E-bay will get to keep those fees.