Lock the lever when you're not using the loader.
Not every time, but like if it's on the tractor and you're mowing or running (and paying attention to) any number of rear mounted implements, especially on the move. And always on the road/highway! Raise it up a foot at least and lock that lever.
I've turned in my seat in heavy winter gear to watch operating the box scraper and my knee-to-lever unnoticed brought me to a strained stop when the bucket got dumped and the lead edge caught the ground, on the move. Not nice for the loader hydraulics either!