The failure rate waving is quite a stretch though. If you take into account reporting rates and time (since most people do not have the watch for long) I'm quite concerned. And I own a PT2. The "look big number, it's not a problem" does not translate to actual sensible failure rates.
To be clear: 51 broken screens in less than two months results in a yearly failure rate of over 1% which is find quite high for a watch.
The fact that he's putting his money where his mouth is (replacing all broken screen PT2s for the foreseeable future) is what gives me confidence that the rate is very low, even if his number is not quite right for the reasons you indicate.
Some people just break screens
What would your acceptable failure rate be?
Less than 1% yoy combined. This is far over that when you combine all failures. Battery degradation is of course excluded.