Could be that at high enough rpm it would self-generate enough to boot-up without any starting current from the dash, particularly an older alternator w/ residual magnetism. I didn't try it without any bulbs.

My owner's manual says that if the "charge indicator" bulb doesn't light when you first turn on the key, to immediately take the car to the dealer for a critical repair. I am guessing the dealers appreciated that - change a light bulb, charge $100. I like the idea of permanently installing a resistor to bypass the bulb. However, it would probably have to be a 5 W resistor. The factory probably didn't do that because such resistor is fairly large and expensive, plus why starve the dealers of income. Rich Mercedes customers normally have regular contact with their dealer to at least change the wiper blades and re-fill the wiper fluid, while they sip complimentary cappucinno.