[foobarbazetc]

It depends on your targetSdk. It can't be enabled by default because it breaks a lot of apps.

[ZeroGravitas]

You're currently downvoted, but you're correct. Apps targetting older sdks will need to opt-in to make use of the acceleration, even on ICS. But it's an easy switch to flip, assuming it doesn't cause visual glitches, which it can in some cases.