You'll know you have a burnout when a gob of lit tobacco drops in your lap.
Years ago I had a customer in my store who wanted to take up pipe smoking. He only want the "best" pipe and tobacco. I sold him a new Castello. A week later he came in and showed me the Castello had a hole burned right through near the bottom. I gave him a new pipe and advised him against puffing too hard or smoking in the wind. In about another week he came in and it was the same thing again. I tried to discuss it with him but he was irate that I had sold him "defective" pipes. I told him I had smoked Castellos for over 35 years and had never had a burnout, or even heard of one. Finally, I gave him a refund and told him I would not sell him any more guaranteed pipes. I never saw him again. Good riddance.