You're in a museum. You're looking at these, a foot off the ground, below a display case. Which are you expected to play with?
Now imagine you're a three-old child. Hint: if you start playing with the flap on the right a moany-faced man will start up his moaning machinery until your father directs your hand to the button. Why didn't they use covers which aren't openable by kids?
The National Museum of Scotland has many 'play pods' interspersed throughout the museum, between the more adult-friendly displays. This leads to a less-subtle form of dissonance. In one example on the bottom floor, there are some blocks which you can assemble to illustrate the strength of a Keystone Bridge. My first inclination was to demonstrate this literally to Nils by getting him to sit on the keystone. However, this involved getting some shoe marks on base of the display. I was soon told to get him down and "please wipe off the shoe marks". Perhaps I went a little too far here, but nevertheless the point is that you are always questioning exactly what you're expected to do: encourage interaction or enforce a barrier? This adds stress to your visit and makes you less likely to come back again. This is surely not the intent.