A mask is a “sign of the sheep”.
Yes. I commented yesterday that my neighbor has horses, which have a pecking order. Sometimes a new horse visits, and the leader gets a big aggressive. The owner then puts a mask with eye holes on the offending horse.
The offender then calms down.
It’s the same principle as used on dogs with the Halti head collars.
The mere presence of the strap across their muzzle makes them complacent, like a mother dog mouthing her misbehaving pup.