Re: Who the [censored] does this?
I feel for you, been there.
I make many sets ahead of time.
Years back, I had the same problem as you. Before the season, I pre-made dirt holes and beds (no bait) for Fox and pre-dug pockets and tunnels for Mink.
When I got to some of my pre-made sets, I discovered traps set in several beds, pockets & tunnels I pre-made. It was frustrating and worked me up, but I never touch the fellas traps or sets, although I wanted too.It was then I realized I couldn't be at every location at 7 am and there are other trappers around.
I learned from those mistakes and nowadays cover/hide my pre-season work.
This may be hard to swallow, but forget about it and learn from this experience. Hide your pre-season work.
Learn from each experience, Learn to deal will completion, keep a level head and use your woodsmenship.