There was an official poll on the question some time ago labelled this way:
"Are you in favour of automatic bid if it's only for Supporters ?".
The "no" won.
Keep in mind that any website needs money to live. If people become Supporter, it's some money. If they aren't, they have to come on BB and hopefully not use adblock.
But everybody could vote in that poll, right? I mean, it's difficult to manage that, but if you're trying to put something new in the game just for the Supporters, it would make sense to just ask them in order to get them happier. So, how are the ones that maintane the game?
If I never thought about making myself supporter, I would not agree with giving them advantages either.