I was looking into Brother (again) as a result of this post, and it turns out they also have their own Instant Ink-style program, with the same "cancel and we'll trash your still-full toner cartridge" terms[0]. Though, perhaps unsurprisingly, it does seem like they do a much better job about making it clearer what you're opting into, though the "we'll make your formerly-working cartridge unusable" note was fairly buried in the FAQs, and not terribly clear up front.

[0]: https://www.brother-usa.com/supplies/subscription-info/refre...