It would be easy to thwart a laser shield if you knew which wavelengths it blocked, and which it didn’t.
I have owned two military binoculars which had a laser shield. One was a Steiner and the other was Kama Tech tho the binocular was a Fuji.
It actually had the name of an optical filter maker “Corion” on the binocular.
This is basically a wild guess but I wonder if they were intended to block a laser rangefinder which might accidentally harm your eyes.
It would be prudent to block all wavelengths once light is detected above a safe level. I imaging that is exactly what they do.