And for what it's worth, I never got my feathers too ruffled by the Buzz thing anyway.
EDIT: And the notice document says you'll need to snail mail all of the following to our intrepid lawyers in order to opt out: "your full name, address, reason why you want out of the Settlement" -- best of all, a nebulous "proof that you used Gmail at some point after February 9, 2010" -- plus "your signature, and the date." What exactly will be accepted as proof? Convenient how they don't bother to tell us. I'm assuming they won't accept OAuth tokens...
They way a lawyer uses the word "proof" is not remotely related to the way a scientist uses it.
1. If all they're after is an assertion that you've used Gmail in that time frame... well, that's already implied by the fact that you've received a notification of the class action and are replying to it.
2. The notice is written colloquially, not in lawyer speak, and the audience is the general public, so it seems more reasonable to take "proof" to mean "evidence" here.