MINNEAPOLIS // Cabdriver Muhamed Mursal doesn't wear his Muslim beliefs on his sleeve, but he may soon broadcast them from a light atop his cab. Mursal and hundreds of other Muslim cabdrivers at Minneapolis-St. Paul International Airport refuse to take customers they know are carrying alcohol. They don't search bags, but a wine box may be enough to leave a fare waiting for the next cab. Advertisement Now, they may be required to buy different colored lights to sit atop their cabs so airport workers who hook up travelers with taxis can steer alcohol-carrying fares to cabs that will take...