They have to write up a ticket for every trade. before they make the trade. or while they are making it. Guess they could deal between themselves but what do they do if someone else buts in on their play?? It is never a sure thing. I can remember years ago was playing a stock kept dropping kept buying from 30 cents down to a dime. Foned my broker and told him to put in a stink bid for 40 thou at 4 cents.  Market was 4 to 8 cents. While I was on the fone broker told me there was 40 thousand all or none for sale. Did I want it. Said sure. So he bot it. Turned out another broker foned him and said they had screwed up the trade. Would he cancel it. Told them it was for a client so they said well dont tell him. He  said already reported to client he was on fone when I did the trade. They cursed and said they were supposed to sell to someone else. Guess the other guy didnt get his bid in in time. I ended up selling the stock from 40 cents to 1.91. So dont count too much on the conspiracy deal