I think this is what NoyGonnaDoIt was saying, but the REAL reason for those NASA reports are to collect useful information to help us later on down the road. The get-out-of-jail-free part is just a benefit. You should full one out because that's useful stuff for NASA.

I fill them out when ever I do something that I think would be useful, even though I know no one is going to yell at me for. I did some touch and goes in the pattern but forgot to click my transponder over to "ALT." Why? I was in a hurry and didn't do the checklist. Moral? DO YOU DAMN CHECKLIST. I figured NASA could draw the same conclusion and do something useful with it.

That aside... fill it out anyways. Even if it helps someone later on down the road.