Originally Posted by Excargodog

It is ABSOLUTELY discrimination. By DEFINITION:

In plain English, to "discriminate" means to distinguish, single out, or make a distinction. In everyday life, when faced with more than one option, we discriminate in arriving at almost every decision we make. But in the context of civil rights law, unlawful discrimination refers to unfair or unequal treatment of an individual (or group) based on certain characteristics, including:

Age
Disability
Ethnicity
Gender
Marital status
National origin
Race,
Religion, and
Sexual orientation.


Lawful vs. Unlawful Discrimination

Not all types of discrimination will violate federal and/or state laws that prohibit discrimination. Some types of unequal treatment are perfectly legal, and cannot form the basis for a civil rights case alleging discrimination.
........

Unfortunately for your "friend", an airline choosing to discriminate between a military member with good judgment and a military member with pi$$ poor judgment is not in the least illegal.