I am working on a SMS (text message) service. Customers will receive text alerts to important information. The message will inform the user they may reply "STOP" to opt out of future messages. This is, to my knowledge, fairly standard.
My question is, if someone replies "STOP", should one final text message be sent back to inform the user that they have been removed from the service and will no longer receive text messages (and possibly a sentence explaining how to opt-in again, should they decide to do so at a later date)
I always feel that providing feedback is important, but in this scenario you could be costing the user money in text message fees from their cell phone carrier by sending the extra message. And while each message likely only costs 10 or 20 cents, it also seems bad to do what the end user just asked to you stop doing.