I loan very few tools. A couple of my friends I would trust with my life...the others I wouldn't trust with my trash can.
Some time ago I learned that most folks intentions are good but they forget like I do. So, to remember what tool is where I have a little pad in the shop and if anyone wants to borrow a tool I simply make them write it in the book and initial it. You'd be surprised how that alone cut down on the borrowing. Go figure?