We went (last week) to this walk up by the Fine Arts Center in Port Angeles, and I discovered that my children approach art in a similar way: they gaze at the piece in question, and then try to climb and/or sit on it.
I'm going to call it "experiencing art tactually" or something else that makes them sound like critics rather than like children who like climbing things.
I feel that Margaret would be a hit at the Louvre. In a few years. When she can climb better.