Black-hat SEO Earns BMW.de PageRank Zero

For your reference – a warning call via IM transcript:
bq.. Ken Schafer: What’s the point of having a site if it can’t be found?
MarketerDood973: None.
Ken Schafer: What’s the number 1 way people will find your site?
MarketerDood973: GOOG
Ken Schafer: Would it be bad if Google banned you from search results?
MarketerDood973: very
Ken Schafer: Would Google be right in banning sites that violate their guidelines…
Ken Schafer: sites that use tricks to artificially boost their rank?
MarketerDood973: Of course they would. Don’t want little scam sites getting unfair ranking. kick’em out.
Ken Schafer: Do you know if *your* site is using any so-called “black hat” SEO techniques?
MarketerDood973: Uh, what?
Ken Schafer: Do you know that your “SEO expert” is living within the letter and spirit of Google’s guidelines?
MarketerDood973: Well, uh, I trust them to do the right thing. They’re getting great results and the pages look fine. I don’t see a problem here…
MarketerDood973: Besides, we’re a big brand…
MarketerDood973: Google isn’t going after real brands, just the little scammers.
Ken Schafer: Uh, what about “BMW.de”:http://www.bmw.de? They just got banned by Google. Check their site – PageRank = 0.
Ken Schafer: Dood – check out “Google Blogscoped”:http://blog.outer-court.com/archive/2006-02-04-n60.html and “Matt Cutts”:http://www.mattcutts.com/blog/ramping-up-on-international-webspam/ if you don’t believe me.
MarketerDood973: gtg
p. *If you have hired anyone to “do SEO” on your site you must immediately look into what they are doing.* You can’t afford for someone else’s “over aggressiveness” to land your brand in search result purgatory.
Could you explain to your boss why your site completely disappeared from Google like BMW’s German site did last week or like Ricoh’s German site is about to?