It's not boater generated. It was likely someone's handline for getting across the creek at lower water. We cut the right side of it today, but the anchor point on the left is a branch overhanging the river that you can't reach from shore or kayak. Two people tugged on it hard from their boats and the branch wasn't giving it up. IMO, it's not really a hazard, now or before, but it's even less so now. At this point it's trailing downstream, with no loops or knots, in the current far river left and not in a particularly rough bit of water.
Damn it feels good