That won't happen. Worst case is that you will get e-mails instead of SMS's. Also the SMS + Hangouts combination is on YOUR end, if other people start using t

That won't happen. Worst case is that you will get e-mails instead of SMS's. Also the SMS + Hangouts combination is on YOUR end, if other people start using the app and sending you messages on Hangouts it's because they wanted to. Worst case scenario here is that you add a friend via Hangouts and you assume it's going to their phone but they only ever reply to you when they're checking their email.