I just want to congratulate the R-Pi hardware designers for making a solid power supply circuit. I noticed a R-Pi 3 Model B v1.2 I had on my desk was quite warm when I accidentally touched the L1, L2 inductors near the power input. Then I measured the +5V GPIO and saw it was +7.1 V!
I was powering this Pi from an external 12V -> 5V converter which connected to the +5V GPIO pin, instead of the normal USB power connector. In turn it got 12V from a regulated supply (which was at +12.2 V) but this piece of ... converter (from ebay) had originally measured at +5.1 Vout, but was now +7.1 V under load, and +9..+10 (varying) open circuit! Shame on me for buying parts from ebay, but anyway just wanted to thank the RPi team for not giving up even with this crazy power input. Thanks!