I lost my favorite ASAT head net out of my coat pocket this Fall.
The next hunt, I had a doe see my "glowing facial beacon" from 50 yards through cover. As I watched her watch me, I "felt" that there was something on the trail just behind me. As I s-l-o-w-l-y turned my head, there was a young doe at five yards! She tolerated the side of my face (with a short beard) with some curiosity but no alarm, but as I came around to where my eyes and skin showed, she "bugged out." On every hunt that followed until I got another head net, I didn't feel as "deadly," whether it was fact or imagined.
I've killed pleanty of deer with my bare face hangin' out, but I go undetected MUCH more often with my mask on. I was really glad when the replacement came...
Your results may vary, but that's my story.