In Twilio[1] a "STOP" reply is an automatic add to blocklist. Their user doesn't have control over how that is handled. I wouldn't be surprised if other provide

In Twilio[1] a "STOP" reply is an automatic add to blocklist. Their user doesn't have control over how that is handled. I wouldn't be surprised if other providers have the same controls in place behind the scenes. [1] https://help.twilio.com/articles/223134027-Twilio-support-for-opt-out-keywords-SMS-STOP-filtering#h_01FBWGDY78H0PYY28VC341JPKE https://help.twilio.com/articles/223134027-Twilio-support-fo...