Patrick,
In the event that an owner neglects to submit a ballot, will the sim vote in their place, sort of like is done for MVP, Cy Young, and Rookie of the Year?
If so, perhaps there can be an "empty ballot" button, should an owner decide that no one on that season's ballot is Hall-worthy, which will allow their participation to still be recognized even if they don't vote for anyone. This would prevent the sim from voting for players who the owner doesn't think are deserving.