i'm sure there's some way that's actually illegal, but i'd bet you, nobody's actually gone to court about it before, and they'd have a hell of a time proving that's what the company did.
@wildweasel I actually have no idea how companies are proven to be guilty of doing something internally except through data and email leaks
on the other end, if you personally hadn't opted out of binding arbitration, and a class-action suit comes up (and wins), would the court be cross-referencing class-action members to the list of opters-out, and be like, "nope, Person Z didn't opt out, they aren't allowed to claim damages"?