Notice that I called it a bit shady. I wouldn't do it, and my trust in people will be reduced if I see them doing it. But it's not the end of the world.
It's not ethical to do this sort of thing because the participants in the auction expect you not to do it. By secretly acting contrary to their expectations, you're betraying their trust. But while it should happen very rarely, sometimes you get into situations like this accidentally or due to insufficient ethical consideration. It's something I can forgive fairly easily if it doesn't become a habit.
The preceding ethical analysis is irrelevant for forum administration, though. Scammer tags are given, in general, to people who break explicit agreements.
Sorry to insist Theymos, but I would like to really understand the logic.
Are you saying that you may create a sockpuppet to support your business ventures and artificially raise price in your auctions "accidentally"? Like it was an accident in the road, something you did not plan and "just happened"?
THEN:
First time you shill bid, it's ok. Second time, not so well. Garr255 did it at least 3 times in 3 separate auctions.
So maybe you are implying that the first time you get caught shill bidding is OK, as it might be "accidental". Second time you get caught, is not forgivable any more.
I don't want to be a pain in the ass, I just want to know clearly what's the position of the forum so I can act accordingly.