The voltages will fluctuate more, or the PSU fans will make funny noises.
Depends on what type of death it is going through, some are sudden and fatal, while others are long and drawn out ones. Random unexplained hangs or instability would be the first sign I would imagine, especially under high load.
He is saying that as the PSU is not being used to cool the CPU, entirely different league of heat output.
PSU's are designed for cases and proper cooling solutions like the PC7+ and a Big Typhoon say. The NT06 Sugo and PSU combo is not even listed on the Ss website as a passive solution. That puts some 20+ maybe more degrees into the PSU over a fan cooled CPU.
I would be amazed if the 20+ was only 10+, its a awful lot in PSU temperature terms.
You read far to much into what he posted there, and basing your comments upon a shaky basis of a poorly cooled CPU.