AFAIK, Chrome extensions don't go through a review process. SmoothGestures was just one extension that got a new developer and then started submitting every visited url to their servers.
Well, there's certainly some central control even if it's not formal review. Of course, review wouldn't catch everything anyway (I think the ability to identify and block bad actors is more important than the a priori review).
It's not watertight (as the recent abuses in the chrome web store illustrate), but it's better than nothing.