[ameliaquining]

No, the mugger getting the money counts as negative. "Now, as an Act Utilitarian, I would happily part with ten pounds if I were convinced that you would bring more utility to the world with that money than I would. The trouble is I know I would put the money to good use myself – whereas you, I surmise, would not."

[uoaei]

No, it doesn't. People having money is Good under utilitarianism because they can utilize it no matter which person it is.

Utilitarianism does not benefit from covert insertions of specific moral carve-outs. Surmisal does not impact outcomes only predictions of outcomes. It is not appropriate to make judgments based on surmisal because utilitarianism can only ever look backward at effects to justify actions post-hoc. This is the primary flaw with utilitarianism as a moral philosophy.