[cjbprime]

The counter-intuitive finding here -- which is in favor of rule-utilitarianism -- is that everyone trying to optimize every difficult decision does reliably lead to unpredictable consequences that are worse than the "follow a rule that would lead to optimific outcomes if performed by 99% of the population" set of consequences.

That is, you can hold a belief that the optimal "decision criteria" for an act-consequentialist is actually a rule-consequentialist one, and this belief is fairly common.

Restated: being an act-consequentialist doesn't absolve you from having to determine act-consequentialism's best decision criteria, because if it did then you wouldn't be being act-consequentialist about it. It's recursive like that.