Some of our users have requested the ability to flag a message as "do not forward". We do not want to use the overkill that is Microsoft RMS (Rights Management Services), but I'm curious if a transport rule could prevent forwarding based on a classification or similar? Anyone tried that?
It sure looks like it could be done with Exchange's transport rules' actions to reject and/or delete the message. The harder part might be building the conditions and exceptions to allow the initial message through but not any later forwards or replies...
So it seems to me is the answer is a qualified yes: Yes, you could implement something like that, but it would not be foolproof... because anything the sender could set in the original message could be removed by the recipient before forwarding.