If you have ever carried a rifle/carbine with a sling attached in a vehicle.....it don't take more than a couple of gun fights to convince you what a bad idea rifles/carbines with a sling attached are. Every time I see the "What Sling Do I Need" threads I always think one you can easily jettison before you put your rifle in your vehicle.Yeah it is a preference thing I got hung up one time in a fire fight getting out of a vehicle and swore I'd never use a sling again. Longest 5 seconds of my life getting un hung.
Murphy's Law. If it can go wrong it will go wrong and at the worst possible time.