The runepools have been around forever. If someone is sitting on 50 abominations (for example) then he has already made the decision not to donate them. So is see no value in not letting him forge them all at once. Moving forward it is likely that he will forge his extras as he gets them, so it's kind of a moot point either way.
I believe this is erroneous. One does not make the decision to not donate - unless they consume them for something else (rune forge). I have a bunch of runes I haven't donated. But I've randomly given out runes to a couple dozen players I've seen kicking around the New Player's forums because I had spares..