I've got no problem with legitimate emergencies, even if they were a little fool-hardy, I'd be in a mighty fragile glass house to claim otherwise. Sandbars and ice-sheets shift, logs and other obstructions float about in the water, sometimes just barely visible or even barely submerged. Out on LOW after several heavy rains there were large "rafts" of peat-moss floating around that were very hard to see until you were basically on top of them, especially once it got a little windy/lumpy.
Where I absolutely believe people should be charged up the wazoo is for things like driving around the "Road Closed" signs/barriers when the Interstate is shut down due to bad weather. In that case, if you need to call 911 because you were that dumb, you should have to pay the hourly salary and mileage of every single responder/vehicle as well as the cost of any materials they had to use/procure.
Or, let's say your house/business burned down and it turns out you set the fire yourself on purpose. In that case, Ins denial as well as restitution for all emergency workers is warranted IMO. Worse would be you chuck your ciggy butt out the window and start a fire out in the country, you should be charged for all of the emergency services as well as the opportunity cost of the burned up grass/crops/etc for that entire growing season.
