Earlier quoted context omitted.
Isn’t it case sensitive? At least I always assumed it was.
For short codes in the USA, it technically does not have to be. And in fact businesses have to regularly check for requests even like "please don't send me messages" to be compliant.
That's only vaguely true. The FCC has effectively said "here's a list of words that are considered reasonable opt out words and let the courts decide what is reasonable when there is a dispute." [0] They're basically deferring to the courts to determine reasonableness.
Obviously it's a good practice to remove people who are intentionally obtuse, but the courts really don't like people who don't follow the instructions, especially because sending "please don't send me messages" is more inconvenient than sending "STOP":
> The court held that “[t]he totality of the plausibly alleged facts, even when viewed in Plaintiff’s favor, militate against finding that Plaintiff’s revocation method was reasonable.” It also rejected the notion that there is something improper about prompting called parties to text “STOP,” explaining that “heeding Defendant’s opt-out instruction would not have plausibly been more burdensome on Plaintiff than sending verbose requests to terminate the messages.”
[1]
That said, it's reasonable to expect that replying "stop" regardless of case should stop those messages from coming through.
[0]: https://docs.fcc.gov/public/attachments/FCC-24-24A1.pdf
[1]: https://tcpablog.com/2017/revocation-consent-must-reasonable...