I can understand why you shouldn't incentivise someone to possibly torture lots of people by being the sort of person who gives in to Pascal's mugging (in the original formulation). That being said, here you seem to be using Pascal's mugging to refer to doing anything with high expected utility but low probability of success. Why is that irrational?
Actually, I'm using it to refer to something which has high expected utility, low probability of success, and a third criterion: you are uncertain about what the probability really is. A sweepstakes with 100 tickets has a 1% chance of winning. A sweepstakes which has 2 tickets but where you think there's a 98% chance that the person running the sweepstakes is a fraudster also has a 1% chance of winning, but that seems fundamentally different from the first case.
I'm currently unconvinced either way on this matter. However, enough arguments have been raised that I think this is worth the time of every reader to think a good deal about.
http://nothingismere.com/2014/11/12/inhuman-altruism-inferential-gap-or-motivational-gap/