Maybe she could (not like she is obligated to but she could) offer a better explanation.

Maybe someone else purchased expensive tickets to something and it would be inappropriate for her to cancel, maybe her family would be upset that she cancels on them and their plans, maybe she has a date with someone who is visiting, maybe she has health problems and need her rest etc

If this event is planned before she knew you are visiting, then it would be hard for her to justify canceling her plans. She could just explain it better

Now if she discussed your visit with you and you made plans already and then sgd says “oh never mind I have plans” then it’s rude. But if you decided to travel to see her without discussing it with her, then really she can’t be expected to change her plans. All she cdn do is offer better explanation