Affiliate Marketing Secrets

I work in a historic museum that is well supported by its community and the city. One day a customer came into my organization looked around, and started suggesting that we sell more framed prints in order to make a profit, she said, “you could make a profit”. It seemed like she was unsatisfied with the museum, it is a small museum, but it has its purpose. it was like she was unhappy with the tourism aspect of our organization. Is it appropriate to suggest something like that to an organization that is non-profit. It is our members, visitors, patrons, and trustees that make our organization what it is.
Was it rude of her? She was not a member, and she was not affiliated with the historic association by business. She did not even hand over a business card. What do you suppose her motive was? Would you ever just walk in to a non-profit historic organization and start suggesting things tp sell in order to make a profit? just wondering…