Interesting scenario, easily fixed with some ingenuity.

If you call her out, you'll make a public scene and you'll have one less player on your team. This doesn't include all the other potential fallout mentioned in the previous five pages.

If you offer to take her and the other two FA's to Starbucks you have effectively ended the original problem, increased cohesiveness among the team, maybe slightly changed her mood or outlook for the day and made Delta look like it has the best leadership of any airline.

As you walk to the coffee shop casually mention you saw someone pulling out their iPhone and it looked as if they were going to start filming her. She will then realize you saved her. Without saying one negative thing to her or giving the general public any angle you have effectively taught and shown leadership for the small price of four minutes of flight time.

Captains, be Captains, leadership is not a natural ability and requires effort. It's like a string, gains are made when you pull, not when you push.