Holy cow, this should be a sticky at the top of this forum page!!!
I was surprised that my 1x turned itself on every time I tried to charge it when it was currently switched off, but I just found that quirky without understanding the implications of it.
If I understand you right, it is not possible to charge the phone when it is switched off, unless this default setting is changed.
And further, if the phone is off and the battery is discharged to the point that the device cannot power up when it's plugged in to charge, then it simply will not charge in the "off" state.
Wow