In my experience, police are tipped by the family of missing people that the victim was a frequent visitor of the preserve. The police ask for access, but aren't really equipped to survey / don't have maps, so we join in person. I get the vibe that as folks contemplate killing themselves in a natural area, they visit it more frequently leading up to the event, so it's kind of obvious. I mean, humans don't disappear. If it's a normal person, hiding somewhere, they are either at a friend's house, the bar, or in the woods.
The other category of people are the ones who just kill themselves in the parking lot or guest areas. Truly, these people can fuck right off. Its a horrible thing to come to work and find a dead body hanging off the observation tower.
We manage less than 100k acres, the longest public trails here are probably only 15 miles long, and we have maybe 3 million people nearby. So, people don't usually die by accident on ours, at leat not in mysterious ways. Distressed hikers are usually found by other hikers before dying. Most accidental deaths I've seen have been drowning due to swimming in undesignated areas.
Reflecting on this response, our police might just be better funded than more rural land management areas. Like, the last search i was involved in was extensive and prolonged. On BLM land way out there, maybe people do disappear, but working in environmental lands management has taught me that truly empty natural land doesn't really exist in most places with reasonably sized populations. Chances are, if you walked out there, someone else will too, at least in public lands.