You mean the first day of an NABC they can predict all the hands for the rest of the week? Wouldn't that require them to use the same run for all sessions during the tournament, and in a predictable order?
Or just that from first board of a session they can predict the remaining hands of the session? But unless they can get the first hand ahead of time, does that do them much good? And if they can get the first hand record, they could probably get the hands for the entire session. I suppose someone could play board 1, go to the restroom, enter the board in their phone and get the rest of them -- is that the concern? In any "important" event (like the late rounds of big events like Spingold), players aren't allowed to leave the playing area unsupervised.