Robot.txt specialists: will Disallow: /? work?

need to block google from ...com/?tracking.

[walkman]

Just added this to my robots.txt:

User-agent: Googlebot
Disallow: /?tag
Disallow: /?tag1
Disallow: /?tag2
Disallow:?

it validates with robots.txt checker, but will it do me any good? (or bad for that matter). I want google to ignore www.domain.com?blah since it sees it as a different page, eventhoguh the file is the same and can seen as dupes