I'm curious about the other side here.
What should a pilot do that knows s/he was weak? Those who made it through UPT have to know that they were weak unless they're delusional. Sure there are the guys who put in the extra effort and it makes them better for it. But the guys that aren't going to be an operational AC, or need covering, etc, etc, what then?
If they know they're a drag on the squadron, can you convince them they should turn in the wings? Can they see that themselves? What's the solution?
Just found out tonight that this very thing happened recently where I am stationed. A transition pilot who did average thorugh the FRS has been FENAB (gone in front of a performance board) and has been kicked out of the Hornet community. I di not know if this pilot kept his wings (I suppose he did because he didnt do anything malicious - like unauthorized fly-bys or have a Class A mishap attributable to negligence) but it was more based on tactical performance in the squadron and performance at his ground job and standing within the squadron I understand.
So to answer your question in this case KBAR; if a pilot knows that they are weak in one or more areas then they need to seek the plentiful help from within the squadron. I have seen very few ever voluntarily give up their wings (meaning giving up flying not actually having their wings taken).
USMCFLYR