It took a passengers side buckle on the front of the fender from some sort of a parking issue from a previous owner. (they told me thier mom hit a shopping cart return post) and it looks like just that.
Just enough to push the right fender back to the door edge.
I measured the frame points to points and it is still square though, so I added the subframe connectors and that it'self made a huge difference.
In my car the rods in the doors for the latches and locks rattled because the fiberglass weave around the rods to silence them was toast, so I split peices of 5/16 poly tubing and slid them over the rods where they went through the guides made into the inner door.
All silent now.
To answer your question about a hit and more flex afterwards, I totally agree with you on that theory.