I think maybe they compare to other shoppers photos, as in maybe they have a database. Now, that being said, I figure it's automated, so it's probably a program trying to compare photos and much like a Google photo search.. it's probably matching photos by how closely they resemble one another, which isn't the best and brightest solution, given how many pictures of similar things are being taken. Don't know what the solution is, but geez.
I know someone else who emailed for the appeal. She did eventually get a response.