for the record, like some others, i don't think it's rigged at the top 15 sites (took 15 sites to be the major ones).

but it isn't testable even with a big flow of cards.

they could just a juice a few in-house players cards fairly regularly. you'd definitely need every player's card flow and a huge number of hands for each.

you could probably prove though that the general card flow is pretty much correct i.e. worst case they are just juicing it slightly.