I was wondering about this too. It could be a an android using something like airdroid and still provide people with the opt out messages sms always should hav

I was wondering about this too. It could be a an android using something like airdroid and still provide people with the opt out messages sms always should have. Putting a keyword at the front of outgoing and incoming messages might be able to help as well if a users phone number was tied to more than one service.