in general I avoid paddling in, around, or over manmade structures, that even includes artificial ww courses! I rarely “play” under bridges, since there is often manmade debri there as well.
One of my favorite runs has it’s share of rebar, chunks of concrete. and other debri but I’m pretty cognizant of where it is (scouting at low flow) and work to avoid it. Yes, I’ve run a few dams and even purposefuly surfed in spillway outflow. So I have made exceptions when it suited me. I think in general, folks underestimate the dangers of manmade structures- be it a cattle fence, a low head dam, a spillway hole or backwash, and often even breached dams have unseen debri.
I think each of us needs to be prepared (skillset and gearwise) for whatever environment we choose to paddle in. “Flatwater” can be anything but flat.
Ocean and Great Lake paddlers got way bigger kahunas than I do. That water is deep and you can be a long way from shore. Then you throw in currents , tides, wind, water temps, and ocean critters and there is a lot to consider.
As far as woodall shoals (chattooga) and the L (big south fork): know the water levels, be on your line, and punch drops real fast and hard (or in the modern age boof) or you just carry around that stuff. Understand that mistakes can have serious consequences. It’s your *ss on the line so you make the decision. “Stuff” does happen.
As far as certification, I am certifiable, just not at a very high level. Certification in general is a good starting point but not the end all be all. This discussion reminds me it’s time for me to again renew my first-aid/cpr and that I have some pretty huge holes in my own game that need to be filled (I struggle with rolling and hand of God).