I know, I did this too recently, but you can build trust.

and I was mentioning my friend to friend example.

Additionally, if someone on gmail had sent me an email, it would go through my spam filters and I would see it.. if I were to reply, gmail remembers that he solicited the conversation and thus I am not blocked..

so it still works, just not so much for initiating conversations, but even then, it'll work after some time.