That bit about a lockable case sending a clear message is spot on, @adam675. I read somewhere that most tool "borrowing" happens because things are just left out in the open. Putting your good stuff away like that really is the simplest fix.

Running a small dehumidifier in the basement for 72 hours straight made a huge difference for me last spring. That damp air just hangs around and you're right, fans alone don't cut it when the humidity is sitting above 60%. If you've got carpet down there, lift a corner to check the pad because mold can start in less than 48 hours. Pointing a box fan directly at the problem wall on low speed helped move the air against the surface instead of just swirling it around the room. It's a miserable waiting game, but sometimes you just gotta check the crawlspace for standing water first.