One of the best female trap shooters ever, Lela Hall Frank, and 2 other female shooters, are shown at the 1940 GAH clearly closing their left eyes; at about 30 sec.

https://www.gettyimages.com/detail/...ion-pile-of-empty-news-footage/502472065

The problem is that the eye wink muscles are bilaterally innervated, and for many it is impossible to shut one eye without partially shutting the other, or with visual distortion of the on-eye with doing so. There is also the fatigue factor, which the tape avoids.

Image of Vicki Ash with totally occluding her L eye, which she no longer does

[Linked Image from photos.smugmug.com]

A good video