This is really bad advice for several reasons, the primary one being that you have far less traction barefoot or in socks than you do with shoes on. Second, if you cut your foot on something sharp, you are in real trouble.

I've crossed many rivers in NZ where you had no idea what was on the bottom because you couldn't see it. I kept my boots on, crossed, squeezed the water out of my wool socks, put them back on and in about a half hour or so, they were dry. No blisters, no cuts. The only time I fell, I was carrying a 40 lb pack, but managed to get back on my feet after being on all fours. I don't think I could have gotten back up if I had been barefoot and most likely would have lost my pack.

fyi, I still have those boots and they look like someone took a box cutter to them-lots of small cuts in the leather all over them from extremely sharp rocks on river bottoms and trails.