Reply #27: In Mexico, it could very well prove to be nothing

[Adelante]

There were three ballot boxes. If voters were confused and ended up depositing ballots in the wrong box, i.e. presidential into local, it would be discovered during the preliminary count and the ballots moved into the correct box, as directed by the district "president." This was agreed to by the parties in advance, as I heard it, and probably happened pretty much everywhere.