Why would friction magically start happening? In MineCraft, you are refering to inertia. Go push a shopping cart at running speed full, then do one with it empty, and the full one will roll further. However, in a 100 mass ship, the measly weight of a player leaving a ship isn\'t going to suddenly cause magical space friction.
Having the throttle set to \"0\" would mean the ship tries to auto-pilot to 0, so it acts as a brake. Just like having it at 75% would run your ship at 75% speed. That way, you just slide the throttle to your setting, and the ship cruises at that speed (like in Mech Warrior, or any number of space/airflight simulation games).