I usually don't trek very far,
when all around me black bears are.
Military surplus tents, especially the older ones, are made from rather heavy canvas, and I doubt if you would want to carry one very far.
I once spent a few weeks of summer in Alaska's Arctic, on Alpine tundra (the first time I was there when it wasn't winter!). I lived in an Army eight-man umbrella tent which I had to set up by myself. But you better believe that I didn't pack it in myself...it was flown in...very heavy...but a nice shelter after it was set up.
I've also used smaller Military tents, but never would include them on a trek due to their weight. Even during World War II soldiers didn't carry a "whole" tent...the carried half a tent, and shared it with someone else who had another half tent.