Should we do most recent login, most points, first account, what? <This is for which account to not block. =
In the past I kept what was considered the "main" account. I also deleted all the votes made by the puppet accounts, but that requires direct access to the database so the mods won't be able to do this. And that problem was partially solved by requiring certain points to upvote.
If in doubt, just keep the account with the highest score.