If someone was to attempt this what sort of things would they do?

I was speaking to someone who sits on his phone talking to a pal as he plays, both at the same table. I tried to guess at what he would be up to but i couldnt. Anyone any idea?
I don't want to try it myself i'm just interested thats all. It was when i listened to Greensteins Ace on The River audiobook that got me thinking of it again. He was talking about how tournament players sometimes sell % of themselves in tournaments and how anything over 5% could be bring about collusion.