Thank you very much ☺
My reasoning was this — Evil things always have a way of getting found. By keeping the watch in the family, the shopkeeper can at least try to limit the damage it does. He could keep it in a safe deposit box but that’s expensive. So, he keeps it in the shop. The new clerk doesn’t know the history and so tags and sells it. It was marked low because it wasn’t working. But as soon as the couple pick it up, it starts working again. I deleted all that from the story because it was interfering with the suspense factor and it was getting super-long.
I hope that answers your question ☺