I interpreted the last statement as follows:
IF you assign a probability higher than 10^(-8) to the hypothesis that you are in a holodeck
AND you win the lottery (which had a probabiltiy of 10^(-8) or thereabouts)
THEN you have good reason to believe you’re in a holodeck, because you’ve had such improbable good fortune.
Correct me if I’m wrong on this.
The person controlling the holodeck (who presumably designed the simulation) needs to know the probability. But the person being simulated, who experiences winning the lottery, does not need to know anything about the inner working of his (simulated) world. For the experience to seem real enough, it’d be best, even, not to know every detail of what’s going on.