Correct. If there’s no hole, it’s a flat set. I’m bad about leaving chain exposed and catch a pile of coyotes. It burying it is not bad advice. Most bury it all beneath the trap but that’s difficult to do in some locations/conditions.

My advice is to bury all the chain. I don't always follow my own advice. If the chain is back in the brush, behind a tree, etc. Not visible from the set itself, I don't always bother. When I stretch the chain out and toss the drag back in the brush or prehook it, I make sure the first few feet of chain is carefully buried, after that I often make sure it is just not readily visible, like I said, back in the brush, or it may just have sticks tossed over it or something so it is broken up and not visible at a glance. I can recall one instance where the chain was completely buried in snow, then the snow melted and a few feet of it was visible from about four feet from the trap on. A pack of wolves came down the trail, got within about twenty feet of the set, seen that, backed up and marked the place all up about fifty feet back, scratches, several piles of scat, marked trees, the works, and left. Leaves you with a kind of sick feeling, but next time through I caught one of them on one of the trees they marked (that chain was carefully covered).