Would it be rational for the Poker houses to try to cheat the rule-breakers?

While I can't vouch for every single poker site out there, the chances of them trying to cheat you are almost nil. The amount of marginal income they would make compared to the risk of a tarnished reputation makes it a foolish play (note that to cheat you, they would need to not only rig the game, but have a shill in there to divert the money to).

I used to count cards at blackjack. And when I did it in Reno, at a certain stage a >new dealer would be brought to the table (outside the normal shift schedule). And >from that point on, I would lose money. If I watched closely, I could see them dealing >seconds.

Unless this was 1950, I believe your eyes fooled you. They would ban you, yes, but the idea of a Reno casino trying to win their money "back" via slight of hand is a little silly.