a priori knowledge of who is registered but will not vote

You can indentify large numbers of such candidates with high accuracy even without complex programming, let alone anything approaching AI, and the number of prospects can be huge in registrars which don't purge dead/moved voters. There is often an order of magnitude more unvoted ballots than the vote margin for most offices and measures.

And generally, the party central committees get both registration data and turnout data for the entire county for free.