For us, I think the state will take any doctor's note at face value. Have never heard of one being rejected. Which is why we have so many here.
As for a kid having a doctors note, but not playing because he's not gotten cleared by the state, that's not my problem nor my liability. If medically he can't play without a tinted visor, then the coach is responsible if he goes on the field without one and something happens. All I'm doing is saying he can't wear one on the field. If he has to sit out, he sits out until the coach can get his paperwork right with the state.