Perhaps it was originally to protect oneself in the face of later reprisals by Spanish overlords. It is nigh well impossible to identify individual Chinelos, apart from height or their shoes. They are completely covered and some even disguise their voices. A bandana covers the neck and chin. The mask is placed over this, then the hat.
Gloves even hide an individual's hands.
To further assure anonymity, costumes are closely guarded and kept secret. Members of the troop dress in different houses to add to the confusion. Thus completely anonymous, young men could view prospective novias or girlfriends as they paraded around the Zocalo. The cost of the elaborate costumes is high. There are professional costume designers, mask makers and beaders, and these men vie with each other to win the competitions, which are now held to judged the best costume.