How often does anyone in attendance scruntize exactly where one person (much less two or more people) are positioned on the sidelines? Likewise, how often do network camera people focus their equipment on the sideline to capture a specific circumstance involving multiple individuals on the sidelines during the course of any game?
That said, it is common for cameras to repeatedly and purposefully search-and-aim at 'controversial' folks during a game. Greg Hardy, Terrell Owens and Dez Bryant are a few examples.
For the latter at the end of the first paragraph, it is true cameras caught Prescott and Sanchez together. How often did that scene get repeated on television screens during any game or the course of the season? Finally, the majority of viewers' and cameras' focus is on the field during any game. How can anything not caught on camera or not witnessed in person be automatically discounted as having NOT happened?