Actually, the way they're implementing this, even if Mozilla decided to try to misuse the data in the future, they still wouldn't be able to, since the data itself is "sufficiently anonymous" (unless of course you want to argue otherwise, like the root comment was suggesting you do).

Or are you saying you're worried that they could _start_ collecting non-anonymized data in the future? If so, I don't really get that argument either. People always have the ability to change what they're going to do in the future, Mozilla deciding now not to collect this data wouldn't change that.