I think you just described how Facebook handles email... But I agree with you for the most part a distinction between known senders and unknown senders would b

I think you just described how Facebook handles email... But I agree with you for the most part a distinction between known senders and unknown senders would be great. The only exception to this that I can think of personally, is for things like the Google 2-factor auth messages which appear to be sent from random numbers (in addition to being random numbers!).