Called social "rp" games are divided to these genres: no rp, rp is accepted, rp is encouraged, rp is enforced. No MMORPG games (in modern times when I write this test) include enforced rp rules.
I mean servers or whole games with enforced rp, that means banning players who break this rule. I have long experience (about 15 years) in few author's games based on this concept. Please send me any questions to PM box, if you need details about.