[Scenario]

pawn Код:

public OnPlayerRequestClass(playerid, classid)
{
    switch(classid)
    {
    case 0: Locked[playerid] = 0; //this one DOESNT.
    case 1: Locked[playerid] = 0; //this one too
    case 2: Locked[playerid] = 1; //this is going to be locked, right?
    }
    return 1;
}

You will notice that each case is in numerical order, beginning from zero. Those numbers are actually skin ID's.