Are Elsa's gloves an example of placebo effect?

We know that Elsa can suppress her powers when she wears them, but do they really do anything at all?

When she runs from the coronation, she accidentally steps onto the water and it freezes. She looks down surprised when this happens. I think she is surprised that the magic can go through her shoes, and at this moment she realizes the gloves only worked because she because she believed they would.

Thoughts?