Ive caught two. One while catfishing for channels with a circle hook and garlic Jello hot dogs and luckily had a buddy with me. We each put a foot on its shell and each used needle nose pliers and got it out. 

Second I caught on a bobber rig for carp with Gulp Corn haha. That one broke off right at the bank. 

Saw this one today.

I "caught" a fairly big soft shell a month of so ago on a texas rig.  It wasn't 3 feet across, but it was at least 2.  I keep a long pair of needle nose pliers in my boat.  I was able to twist the hook out of it's mouth while staying a foot or so away.  I didn't care about the hook but felt the turtle didn't need it in his mouth.   I wish I would have taken a picture.   The next week a snagged a smallish snapping turtle in a back foot with a crankbait(not on purpose).  I grabbed it by the other foot with one pair of pliers and got the hook loose with another.