When you're dating around, you can either get upset every time it doesn't work, or realize that was just one step up THE ONE! And if you're on a journey, you're going to do some learning... but why not get some hard and real criticism where it counts?
This girl's exit interview idea is genius. Look... you have NOTHING to lose after something is officially ended with someone. You only have things to gain. They could think this is hilarious and say "nevermind let's try again," or they could fill it out and move tf on with their life like they planned in the first place.
Either way, it's a win.