I read this a couple of days ago and had never been with a newbie before so I thought you were being unfair to them... oh how wrong I was!
I had my first roll with a newbie. Even though the instructor said before hand to both of us "Go real slow, this isnt about winning is about learning", the guy comes out at full force straight from the get go, I deal with that pretty easy, but it was unnerving, specially when he was throwing his limbs everywhere with little care. I get him in my guard and he starts throwing elbows into my legs to which I say "You cant do that, we arent striking" (I am still trying to be nice by this point)... he stops but didnt say anything. I end up getting him in a rear naked choke, and his reply was a big eye poke as he is throwing his hands into my face. I say to stop and wait, but he then trys to come at me again and the instructor has to step in.
I dont think he will be coming back anyway. And I learnt from you guys the best way to deal with them!