Wierd motherboard issue, wonder how widespread

Helping out a friend (remote) with some PC stuff, they went off script and did some cable management, ending up in trying to start with the CPU power missing.
This was a DQ67OW Intel board, but I turned up a chance result that suggests other boards do this.

It failed to start, and also triggers a lockout that prevents it starting once CPU power is corrected, and yes, it did get switched off completely inbetween.
To release the lockout, you have to clear CMOS, or in this board, a "drain" by using power button with no power achieved the same result.

It almost had me beat, without a lucky google hit, I was close to thinking it had fried the board by pulling too much power through the ATX 24 pin

It must be an Intel thing, or some weird BIOS bug possibly, or maybe some safety thing Intel does? I’ve done this on other mainstream boards (Asus, Gigabyte, Asrock etc) and never any issue once reconnected
We’d have to have some other Intel board users test this to confirm what’s going on