This is such a good idea. Is any interpretation presented along with such
displays? Almost no interpretation would be necessary.  The vast majority of
people are conscientious, once they get it, they happily comply.

Programs in California that stencil the entries of storm drains with bright
blue messages such as "Drains to the bay", have greatly reduced water
pollution. Obviously repeated proximate messages will be more effective, but
more compelling ones may just as good.

Interaction with the half covered display would be so somatic, it should
stay with the visitors much better than a block of text. I find that people
tend to appreciate an idea that they feel originates in themselves. In this
way, a lack of interpretation may actually make such a display  more
effective.

Do many museums do controlled studies of their visitor's interactive
patterns?