MOO, but I don't think they have a specific site, like the entrance to a mine or cave. They have a search area that may be familiar only to outdoorsmen who live in the area and know it intimately. Not a place where the casual hiker is likely to go, but accessible to someone who is accustomed to carrying deer carcasses out of the wilderness to a trailhead. Maybe BM discovered it while tracking a wounded animal. It was the place he had in mind when he told MG he could hide a body where no-one would find it.
The danger of searching may be a factor, but it seems more likely to me that the area must thaw thoroughly to give cadaver dogs their best chance to find the remains.
@Trackergd might know more about this, if s/he is still around.
Still, ITA the site should be monitored. If the SO is serious - and I believe they are - the trailheads and trails approaching this area are peppered with trail cams. I'd love to see BM try to remove SM from her temporary grave.