What is the ruling on a woman traveling to visit her parents without a mahram, and is not visiting them considered disobedience if communication is maintained via phone and they request her visit?

The hadith indicates the prohibition of a woman traveling alone without a mahram. If she finds a mahram to travel with her and her husband gives permission, then it is permissible for her to travel to her parents; otherwise, it is not permissible. There is no disobedience in this, because honoring one's parents is conditional on what is good and not violating Islamic law, and obedience to a created being is not in disobedience to Allah.