I always had a problem with this style of role-playing. I think it's way to easy for the PC's and DM to go overboard with what happens.
DM: A rogue jumps out the shadows behind you and performs a backstab.
PC: Well since I heard him come out the shadows and I know he's inches from my back, I'm going to spin to my left, draw my sword from its sheath and chop his head off with my momentum from the spinning.
DM: The rogue, anticipating your actions, does a combat roll forward, not only sheathing his dagger but drawing his repeating hand cross bow. Ending the roll facing you and on one knee he fires 5 shots aimed at your head, groin, heart, 1 foot to the left of your heart, and 1 foot to the right of your heart. You know that if you try to avoid these shots by trying to move left or right or jumping up or dropping down to the floor will result in you getting shot by at least one of the arrows. You also know that if you perform any of those actions you will be shot in the head, heart, groin or any combination of them.
PC: I use my unsheathed sword as a thrown weapon and chuck it at the now almost prone rogue. I then pull out my shield and drop down toward the ground behind my shield so that the arrow aimed at my groin is deflected.
DM: You didn't have time to throw your weapon and pull out your shield and drop down to deflect the arrow. You are shot in the face, heart, groin and right shoulder as you reach back for your shield. You die before knowing if your sword stuck down your foe.
PC: Wait a minute! The rogue had enough time to do a roll, sheath his dagger, pull out a cross bow and fire 5 shots preciecly, but I didn't have time to throw my sword and pull out my shield? That's BS!
Something like that is what I see happening. Someone correct me if I'm wrong because I've always wondered how those types of role-playing sessions are governed...