Theoretically, if the bubble was clearly marked but not fully filled (maybe a checkmark instead of filling the bubble), the human looking at the ballot could make the intention of the voter more clear by filling in the rest of the bubble.
EDIT: I actually found another post that attempts to explain it here.
There was a woman in the longer video that is copying things from a ballot on the left onto a ballot on the right.
If that's what's happening, though, it is still insanely rife for exploit. This is scary, scary stuff.
In the full video, you see multiple people making markings on different (what seem to be) ballots. Does anyone know of a legitimate reason for this?
https://www.youtube.com/watch?v=JanZbhr1LHs
27:00, 28:00 (in background), 37:00, 38:30 (close up), 40:40, and more...
Theoretically, if the bubble was clearly marked but not fully filled (maybe a checkmark instead of filling the bubble), the human looking at the ballot could make the intention of the voter more clear by filling in the rest of the bubble.
EDIT: I actually found another post that attempts to explain it here.
There was a woman in the longer video that is copying things from a ballot on the left onto a ballot on the right.
If that's what's happening, though, it is still insanely rife for exploit. This is scary, scary stuff.