So, in my last run, I created a container next to the workbench in Sanctuary. Originally it was just going to hold surplus water from the purifiers, but it ended up as a dump box for all the bits of armor and weaponry that I didn't want to junk, but which I didn't want to carry either.
Then I stored a coast guard cap there, and the next time I was in sanctuary, I spotted a settler wearing it. OK, no problem. I wasn't going to do anything with it. So I've started dumping spare armour and unwanted legendaries in there. Let 'em upgrade themselves.
Here's the thing though: once I had once settler with a coast guard cap, they started cropping up all over. In settlements fairly far apart.
Has anyone else had this happen? I'm wondering if it can be used to farm legendary gear. Stick something expected in a box in a public area, then harvest the duplicates back from the settlers, sell the excess and re-seed. (OK, it sounds like more trouble than it's worth, but I'm still curious).