Don't take any chances! IMHO, if I didn't have full detail of the stretch I was running, I wouldn't do it without further scouting. If you are running a small river, one large tree can cause a bank to bank strainer. Nobody is going to tell you to "man up" and just run it. Safety is key. Study the stretch you are planning on. Use maps, GoogleEarth, and any other info you can find. Nobody likes to hear that unexpected sound of rushing water downstream when they can't see it. By all means, if you know what you are getting into, plan possible portages by what info you get. Ground your yak, get out, and physically observe the conditions ahead if there may be any question of its safety, then decide whether to run it or portage. A whitewater kayaker looks for Class III's, and if he takes a dump, he takes a dump. A kayak fisherman possibly is carrying $500 or more worth of gear, plus his own neck, and a dump could prove to be a financial, or worse, disaster. There is nothing "macho" about barreling ahead into unknown conditions, I would consider it stupid, no matter the results.