You are correct that F8 during post wont do a damn thing, but just because you decided to point out the flaw in my wording, I will point out yours. The keystroke actually register after the POST, but just before windows begins to load. If you wait until your PC is actually loading windows, F8 will not do a damn thing.
Now, try explaining how to hit the F8 key just before windows starts loading and just after POST finishes over the internet. The person will probably miss it every time. Jabbing the F8 key during post (and after) will ensure it catches at the right time, which is why I said that.
Very pertinent to this thread though, I will give you that.