Honestly, while this change was controversial, it was very well publicised and displayed to users at the time. I think it is quite a hard case to prove that use

Honestly, while this change was controversial, it was very well publicised and displayed to users at the time. I think it is quite a hard case to prove that users were misinformed - if it it does hold up, it'll create quite an interesting precedent where even executing a change like that with complete explicit opt-in isn't enough to keep you in the clear. It might have the perverse effect of making companies pre-load every evil thing they can ever think of doing into their initial terms of use because it is interpreted as impossible to post-opt-in a normal person in a reasonable manner.