[kem]

I'm a firm believer that poker sites are not rigged. As it is, they already have a license to print money. They make money hand over fist. They have such little overhead compared to a B&M casino, and what casino can seat 60,000+ people at once at their tables, and deal them 60hands/hr? If online poker sites lose their reputation as being fair and legit, they lose their cash flow, and it's a huge cash flow. Too much to lose, too little to gain, they already make tons of money, why would they risk it all?

That being said, there is probably a very low probability that they would be caught if they juiced the deck in a clever manner. For instance, play everything legit until the river. Then, look at the cards of whoever is left, as well as the board cards. Find the card(s) that improve 2+ players hands at once, and increase the probability of that card being dealt on the river ever so slightly more than the remaining cards in the deck. How would they ever get caught?