She had attended Sunday School when she was a child, and remembered the verse from Exodus 3:5. “And he said, Draw not nigh hither: put off thy shoes from off thy feet, for the place whereon thou standest is holy ground.”
She thought, “That’s a good idea, taking off your shoes! But I’m already barefoot, so how can I show my respect?”
Reasoning from her experience with strip poker, and demonstrating her respect for the rules, she did what she had to do. Or thought she had to do.