If you're smart, you only waste a minute.....literally. Just quit when you see that you're backfilling. simple solution.
Now, lets focus on the actual problems not the symptoms of those problems, shall we?
Instead of asking for folks to not quit...maybe ask the devs for a /resign feature? Just sayin'........
A /resign voting system might be the answer...or it might open a whole other can of worms. Not sure how much is incumbent on BW to rectify player behaviour here, beyond applying a minor disincentive. I'd rather players quit than go afk.