If Victoria Osteen really did what is claimed, and there were injuries, I don't blame the flight attendant for suing.
The Osteens teach that God gives favor on Christians and if we just expect it and speak it, everything will go smoothly for us. People will open doors for us, serve us, give us money, etc. It's not the gospel that he teaches. I am not saying that this is why V. should be sued, but undoubtedly she was upset when something was not cleaned up right away. Where was the "favor" that they are always teaching about? That was just not how it's supposed to be according to them, so she probably got upset over this.
They did make the Osteens leave the plane, so something happened.
On top of this, they are treated like special people - look at how his books have sold and the fact that he has the largest attendance on Sunday morning of any church (at least these were the stats a couple of years ago). They are probably used to celebrity treatment. Other celebs have also got upset.
