My trouble with the trolley problem is that it is generally stated with a lack of sufficient context to understand the long-term implications. We're saying there are five people on this track and one person on this other track, with no explanation of why? Unless the answer really is "quantum fluctuations", utilitarianism demands considering the long-term implications of that explanation. My utility function isn't "save as many lives as possible during the next five minutes", it's (still oversimplifying) "save as many lives as possible", and figuring out what causes five people to step in front of a moving trolley is critical to that! There will surely still be trolleys running tomorrow, and next month, and next year.

For example, if the reason five people feel free to step in front of a moving trolley is "because quasi-utilitarian suckers won't let the trolley hit us anyway", then we've got a Newcomb problem buried here too. In that case, the reason to keep the trolley on its scheduled track isn't because that involves fewer flicks of a switch, it's because "maintenance guy working on an unused track" is not a situation we want to discourage but "crowd of trespassers pressuring us into considering killing him" is.