The banners display something that says "Spongetech, America's Cleaning Company" and smaller letters saying "A publicly traded company ticker symber SPNG" something along those lines.
The company paid to advertise in those stadiums, is that stock promotion as well?
If the banners show the company's ticker, then yes, it is. That kind of "advertising", among other things, got CMKX in a great deal of trouble. Theirs is not an example I would choose to emulate.