Minnowbooster is a different business model, it is an instant bid bot. If it cannot do a vote, it doesn't lose money or effect a window with 20-40 other people in it. So it is easy to just do a refund as no vote has been handed out.

If we have a $10 vote, and you bid $5, then we refund you. That $5 is lost, and distributed to the other bidders.