as far as I can tell you have to opt-in to Buzz in the first place.
when mine was activated, I got a splash screen asking me if I wanted to join, or if I wanted to just go to my email.
but then again, I'm probably the only one who got that choice. everyone else was forced at gunpoint by Teh Evil Google.
but beyond that I understand what you are saying.
After reading all this, I went to check my gmail. It prompted me with the same screen and I said "go to gmail" where I turned off buzz and that was that. Of course I don't have a Google Profile created so I don't think any "harm" was done.