I have, and use an ameristep reversible doghouse blind. it has two different camo patterns on inside and outside, and can be reversed by opening two zippers, flip the sides inside out, and rezipped. it has a full floor, and shoot through membranes that I never use, they just fog up. During gun season, I use the camo orange cap that I purchased at the same time. it simply hooks on with bungees, very simple. I prefer to hunt from the trees, for the most part, but when very cold, the pop up blind works well, and with a blanket over my chair, and a small 1000btu propane heater under my chair, i was quite comfy, for long stretches at a time. Are they safe? well, anywhere but on public lands on opening deer gun day, I would say yes, they are just fine. but during deer gun on public lands, I would not be caught on the ground. There are often too many hunters, in too small a space, and no one knows where anyone else is, if they can not be seen, or if they are excited and shoot without looking beyond their target.
I have been shot at without a blind, or stand on public lands before, and did not enjoy the feeling. There are guys who never use a weapon of any kind but for deer gun, and public lands are where you find them. (if they were more serious, they would practice more, and have made arrangements for hunting on private lands if possible.that just stands to reason.) and for that reason, if I happen to be hunting public lands at that time, it will be from a tree, and wearing plenty of orange.
The only real difference between a good tracker and a bad tracker is observation. All the same data is present for both. The rest is understanding what you are seeing.