It work on magpies. When they nest, Maggies "swoop" at people, dogs and such that get too close. In australia (where all birds are much bolder), people do the sunglasses trick.
Later I saw kids waiting for the school bus with ice cream boxes on their head with two dots drawn on the back. Definitely not a fashion thing.
The locals got I good laugh from me getting pecked because they all know the tricks after the first warning swoop.