Seems like this is another discussion we've had before?

In my opinion, this is a bit of a red herring argument.

Caves and mines are a very specific environment, and require specific tactics and training. For example, searching a cave is generally more a matter of searching a defined space, which in most cases can be adequately illuminated with a headlamp. It generally isn't so much of an issue of finding clues with which narrow down the search area, as it is simply looking for a person within the enclosed area of the cave. Caves might be miles long with multiple branches, but except for a few notable exceptions, caves are not wide open spaces. In a cave, your search area is clearly defined. In an outdoor search, we always have to wonder if we've made our search area large enough. A single clue might make you realize you need to expand your search to include the next valley over the ridge.

In wilderness searches, we no longer look for people. Rather, we train our searchers to look for clues. And clues might include many things besides footprints. The subject is a clue generating machine. There is only one subject, but there will be many many clues. In some cases, the absence of clues is in itself a clue. The overall logic is that if my mind and eyes are focused on looking for a person, I might easily miss a subtle clue. But if I'm looking for clues, I probably won't miss a person.

Another thing that is changing in SAR is the emphasis on conducting missions as safely as possible. Back in the day, SAR teams routinely took a lot of risks that we wouldn't take today. And it isn't just about preventing major injuries or deaths. If you twist an ankle stumbling around in nasty terrain in the dark, you are no longer part of the solution. Rather, you have become part of the problem. So the search manager always needs to do a very careful risk/benefit analysis regarding night operations. Or any other operation (including caves and mines).

An analogy might be ambulances and fire trucks. In the past, it was common for ambulances to rush to the hospital at a very high rate of speed with lights flashing and siren screaming. Great fun! Unfortunately, lots of EMS people and general public were killed or injured in accidents involving ambulances. Many jurisdictions are rethinking that, and ambulances tend to go slower and more cautiously these days. Yes, that means a few more patients will die because they didn't reach the hospital within the golden hour. But a lot more EMTs and general public will live because they didn't get in needless crashes. And just like ambulances, fire trucks now drive a lot more cautiously than they used to. And nowadays, firemen always ride inside the truck, belted in. New ambulances are being designed so that the EMT or Paramedic can ride belted in, but still care for the patient.

As I said up thread, it doesn't mean we don't search at night. It just depends.