Just installed these (3/30). Used the video tip where you unscrew the bolt a little, use WD40 or similar, screw it back in, give it a minute, screw out, a little further this time, repeat WD-40, screw in/out etc. until the whole thing comes out fairly easily. I was able to properly fasten things again so that makes me believe the nut part did not come undone. For all I know, though, it is now hanging by a thread so will have to inspect in a few days and few weeks.
One thing I found, in particular in the front, is that the "clip" where the flaps hold on to the wheel well trim is not very deep/tight, and easily dislodged by hand. Wonder if that will hold. Time will tell. (Grommets etc are properly aligned and I am confident the installation was proper).