Futarchy: Cancelling trades?

[Chralt98]

Hey team,

I don't understand this.

This means that the CEO actually gets fired and the trades of $M_1$
are cancelled (this is done as we have no way of ever knowing what the stock
price would have been if the CEO had remained in place). If, on the other hand,
the estimate of $M_1$ is larger than that of $M_0$, then the CEO keeps their job
and the trades of $M_0$ are cancelled.

If you cancel trades what does this actually mean? I would expect it's a refund. But how is the estimate made? If it is made by a market, there is skin in the game, I understand this. But as soon as you cancel / refund the trades, there was no skin in the game.

Are both scalar markets simultaneously running and then the decision is made to either fire the CEO or not based on a specific future price point and then refund one of those scalar markets?

[Chralt98]

Seems like a trader doesn't know which scalar market actually will be refunded, before the point of the decision to either fire or not. So that's why there is always skin in the game, right?