It's just money to the sports teams. They would gladly take it if Delta offered it.

I flew one of the USA national sports teams to an international match. As they were getting on the airplane, one of their handlers comes up to the flight deck and says something along the lines of, "Hey fellas, if the plane feels a little heavy on takeoff, no biggie, you have the USA Men's National *insert sport* team onboard!"

He was trying to be friendly. The USA men's national team for that sport is sponsored by Emirates, and they were wearing matching shirts with the Emirates logo on them.

The captain, instead of graciously saying, "Thanks for the tip! Good luck in your match," goes on an anti-Emirates rant. "How can you guys wear shirts that say Emirates while flying on Delta!? Isn't that anti-American!? Don't you care about the American worker!?"

I tried to gently back him off of his diatribe, but he wasn't hearing it. The handler left the flight deck insulted, and the captain spent the rest of the trip bragging to me about how he really showed the Emirates t-shirt wearing guy.

Maybe we shouldn't criticize the sports teams for taking the money. I mean, I'm sure they'd wear shirts that said "Captain Grouchy Pants," if guys were willing to give them the money.