Perhaps the best policy against vote-stacking:
1. Run a checkuser on all accounts that ONLY participate in the AFD concerning
the article.
2. If the checkuser is positive, block the user for sockpuppetteering for a week
and leave note on talk page.
3. Block sockpuppets indefinitely.
This might deal with AFDs on 'fancruft' and other controversial matters...
certainly worth a try!
Craig