Penny hasn't shown any interest in it, which is great. But of course we humans can't leave well enough alone, so I threw a treat into the garden to lure her in there and see what she would do.
The butterfly fluttered right in her face and she ignored it. Hooray!
And I think it's doing its job. If you look carefully at the last part of the clip, you'll see a cabbage white fly to the tomato plants and go away when it sees the artificial butterfly moving around. The idea is that these butterflies are territorial and a female won't lay eggs on plants if she thinks another butterfly has already laid eggs there.
Look how delicately Penny backs out without damaging the baby tomatoes and basil. What a clever dog!