I was suspicious of the fairness of the doubling on English Harbour's video poker. So I deposited and carefully recorded data for over an hour, doubling after every win, except I collected any large wins, and recording for each double the result, win, lose or push.
I played until I lost all my money (playing 4 line, single coin, recording wins, losses and ties on the doubling game (I did not record the video poker itself - I was only concerned with the double).
According to my data, it is 99.999% certain that English Harbour is not offering a fair doubling game in their Tens or Better video poker game.
Although nothing is completely certain, 99.999% would be good enough to convict a man and sentence him to death, so I think it is good enough for any reasonable person in the world to be satisfied that English Harbour is a cheating casino.
Here are my results:
84 wins
151 losses
19 ties