It is true. The NFL players and coaches are charged different state taxes because they worked in that State for the income. If the game is played in CA, CA gets taxes on each players and coaches earnings. I work in the banking industry and have done a few mortgage loans for some. The taxes that come out of these checks is unreal. You hear about the huge salaries these guys make but to see it on a paystub is pretty amazing.
But to play a lot more games in FL and take advantage of this no tax thing is HUGE, so it is still a selling point. Plus the weather, women, and the night life sells it self as well.