Remind 101

Remind 101 is a website that allows teachers to text students and/or parents with updates and reminders without anyone having to know anyone's cell phone number!  It even lets you set up messages to be sent at a later date & time.  They subscribe by texting your "code" (provided by the site) to a phone number (also provided by the site).  Their name will show up on the subscriber list.  It even lets you edit the names.  So they might text in that their name is John Smith, and you can edit to say John Smith - Sara's Uncle.  Way cool.  The only thing I can't figure out is how a subscriber can stop subscribing, except to contact the teacher and ask her to take their name off the list (managed on the site).