I don't think the use of bidbots will automatically earn you flags. It's more when you are perceived to be abusing them. Of course, exactly what that means is a little different for everyone. But when someone posts spam and uses bid bots to pump it up to $75 or more, that's obvious abuse. I don't think you have anything to worry about in your case but I also don't know if an investment in bid bots will really pay off or not either.