I don't know why it is that suddenly this is a "pissing match."
The FACT (not piss) is that you are incorrect.
That does not make you a lesser person, you are simply incorrect
THERE IS ENOUGH parasitic load on ANY car (even older cars, diode leakage or just plain dirt and corrosion) that a voltmeter and ESPECIALLY a modern high impedance digi meter, will simply show battery voltage with NO load other than NORMAL parasitic drain.
And..............any modern car with a memory device, IE radio or engine computer will MOST CERTAINLY show battery voltage if a voltmeter is used in this manner.
THE FACT is that using a voltmeter as you describe shows you NOTHING meaningful. NOTHING
You MUST measure current.