I would challenge both absolutes in this exchange. “Always underexpose slightly” leaves image quality unused in many situations, while saying that “zebras show the actual raw latitude” overstates what the camera is measuring. The camera’s exposure aids are valuable, but they remain processed indicators that must be interpreted—or experimentally calibrated against the raw file.
When making an image in the field without a large calibrated display and the ability to inspect the raw file, the photographer has to decide which highlights must be preserved and which ones can be allowed to clip. We all understand that.
The problem, in my opinion, is that an in-camera meter and its exposure aids come with the manufacturer’s assumptions and processing choices built in. A separate reflected-light meter also provides a reading based on its calibration standard; it still cannot know which parts of the scene you consider important.
If you had the time—and were working from a tripod with a calibrated MacBook and RawDigger—you could examine the raw data and determine precisely which areas and color channels had clipped. Under normal field conditions, however, most of us rely on experience, including lessons learned from past mistakes, to estimate the exposure. With familiar subjects and lighting, that estimate is usually quite good.
Modern cameras can handle many backlit situations remarkably well, but they cannot eliminate the dynamic-range problem. With a scene such as the backlit woodland examples in this discussion, you may need to make several exposures and blend them to taste in post-processing. In that sense, we have come full circle to the film era, when photographers bracketed exposures, combined negatives, accepted a compromise—or simply turned the camera 90 to 180 degrees and found something else to photograph.
I digress, but for sunrise and sunset scenes, a 0.9 or 1.2 reverse graduated neutral-density filter remains one practical solution. It is not perfect, but it is often good enough. In suitable scenes with limited subject movement, an in-camera HDR or exposure-blending feature can also do much of the heavy lifting.
Ultimately, neither the meter, histogram, nor zebras can decide which light matters to the photograph. They provide information; the photographer still has to interpret it.