E.g. "Should I install a fire-alarm with 100 dollars for the purposes of early warning in cases of a fire?" "No, I will have then less resources in case a Matrix-Lord comes with evidence and requires them of me." A mind that utilized such a logic would no longer even need a mugger in the first place to fall into insanity...

I am reminded of the Island Where Dreams Come True in The Voyage of the Dawn Treader, which is exactly what its name says. Not daydreams or longings, but all of your worst nightmares. Having once imagined a thing calls it into existence there.

The muggerless mugging follows from giving a hypothesis some credence just because you imagined it, otherwise called the Solomonoff prior. I recall Eliezer writing here some years ago that he did not have a solution. I don't know if he has since found one.