That doesn't make sense -- the parties to the conversation already _have_ the messages.

Spam prevention is a likely angle, however. EU should force it to be opt-out, not opt-in -- probably what people want anyway.

I would like to be opted out by default. I'm worried at least one of those new services is going to get overrun by spammers, and if I'm opted in by default they could use the gateway to whatsapp to spam everyone else.