I unfroze many seized engines, and the rings were still ok. But once the piston collapses (at the ring lands) the ring sticks, and gets smeared onto the cylinder wall. I.ve seen that many times. That and the ends of the ring coming together and breaking the ring because the lack of end ring gap. I have never seen signs of scoring just because a ring got too hot. Im retired from the motorcycle/automotive industry though. These little engines may not be quite so tough. Normally if you lightly seize a large 2 stroke, Motorcycle or scooter, as soon as it cools, it's good to go again, unless ya really roast it. Maybe were both right, and I have just never seen the situation your talking about, or i've been mis-diagnosing some of the results i've found. Outside of lack of oil in the gas, or bad tuning or vacume leak, I don't think you can overheat one of these little engines. I've never hurt one. Come to think of it, outside of a timing belt on a pinto, i've never had an engine failure.