the clients obviously want to play the game if they are connected, and the server needs to serve, developer should have access to ping the client.
I remember speaking with Lummox a long time ago and he said pings are tracked internally, it's just a matter of making it available for developers. I would be very happy with just being able to ping whatever clients are connected rather than being able to have the server ping any address.
A lot of people block ICMP requests... That's why having a built in one would be great.. considering you know, the clients obviously want to play the game if they are connected, and the server needs to serve, developer should have access to ping the client.