[sKenzi1996]

1.

Код:

public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
	if(vehicleid == examen[0] || vehicleid == examen[1] || vehicleid == examen[2] || vehicleid == examen[3] || vehicleid == examen[4])
	{
		SendClientMessage(playerid, -1, "INFO: Those cars can be used only in exam");	
		RemovePlayerFromVehicle(playerid);
	}
	return 1;
}

Full code.

2. Nope, i have 4 cars, if 1 of them is busy, remains 3. So, put that player in different car. You have the answer?