I know this is going to sound crazy, but they actually televise games where you can see with your own two eyes -- teams signaling in plays from the sideline. Crazy, huh?
And if your job is to try and figure out the signals of opposing teams -- I'm going out on a limb and saying, you've watched a lot of videos (legal and in stalions case, illegal) -- so you come up with a template of what you THINK the signs mean.
Then when you see signs coming in, you try to figure out what is real and what isn't.
Should I go back and number each point for you? That seems to be your thing. It is rocket science though, even though you are trying to make it out to be.