Suggestion to make the DM's safer

A lot of creeps tend to send a lot of creepy pictures such as d*ck pics. There is nothing you can do to protect yourself against that sort of disgusting attack so here is my very simple idea: An option where messengers can only write you when you accepted their request. And only then (when you accepted the request) you can see the message. That way we have more controll over what we want to see and not want so see.