[kogir]

I think they also want any impromptu benchmarks people run to be as fair as possible. To the best of my knowledge, the latest FF and Safari both have all their supported hardware acceleration turned on by default.

I've met some members of the IE tech team (who don't control the marketing). The people I know really want to win without cheating and support as much as possible, but are very wary of releasing anything too early. They're very careful to wait until the standards are pretty precise and stable before releasing an implementation, lest they be accused of trying to "sabotage" something with an unintentionally different (but still within the vague spec) implementation.