Since this is sold I won't be stepping on any toes to post...
The outlet isn't the problem in most all of these situations. If this high-dollar receptacle had been used but installed in the same fashion it would have melted too. There's no 14-50R that can withstand continued 80% draw when the leads aren't properly landed. I've seen a bit of insulation get caught under the terminal as the screw was tightened down being the culprit in many of the situations people have posted. This is somewhat common but the continued and sustained draw amounts these cars pull is what reveals the faulty installation. If that was used for a dryer, welder, etc. it likely would never be noticed. People seem to get the wrong idea that if they spend $100 instead of $50 on an outlet it guarantees a safe installation which is a false sense of security I'd prefer not see perpetuated. Sure, it can't hurt but it's not the solution to the potential problem.
Moral: Make sure your outlet is installed properly and that you use good electricians or (if done yourself) you know what you're doing and secure everything properly and use the proper materials for the installation. I pull mine out and check it regularly and that's about the only time I even unplug the UMC from that receptacle. Install it right on the front end and check it regularly during use (for excessive heat) and when not in use (when you can remove the receptacle from the box and examine connections & wire/insulation) and you MAY not burn your house to the ground.
I'll take a $50 outlet installed by someone who knows what they're doing and does a proper job over a $100 outlet installed by someone who may or may not know what they're doing but doesn't take the time to install it right either way. That said, nobody said you have to choose one or the other so both the $100 receptacle and proper installation certainly wouldn't hurt. Just don't lose sight of which is more important when it comes to running a sustained 80% of a rated circuit's capacity on a regular basis.
