I collect old bed frames and funky used plywood.
Let the frames and plywood get good and rusty / funky.
Make your tree stands out of the weathered materials, but put a solid piece of ply between two pieces of funky ply.
After you make them let them sit outside and weather a bit more - - -
The seel frame still has plenty of strength but they look like crap, and even appear dangerous to the untrained eye.
Find the nastiest rusty old (but strong) hardened logging chain to secure them with "aged" good solid locks.
I have not had one stolen in years - - - most folks are afraid to put any weight on them
Surely you can imagine this in "bedfram and old ply" - - -