you should be required to practice a champ 10 times in normals before you can play them

I just got forced to play adc. I was last pick. Everyone agreed on a lane that they wanted, I called top and someone called adc. For some reason the person who called adc decided to lock jax, a champ he has never played before when I expressedly said anything but adc, its my worst role. Thats fine that I had to play adc (I did terrible because like I said its my worst role), but why would you auto lock a champ you have never played before when someone else says that they dont like adc after you call adc...