It is FACT, you dont need the 12Volt switching signal on an scart cable.
I have worked with different type of problems relating to scart connections between equipment and having 12 Volts makes no difference to operation apart from switching the TV to an AV channel.
Even with newer TV's its used for switching to AV Channel. Some sets use some other unused pins to transfer data, i.e. Sony's smart link. The Amiga however would never use the smart link pins.
Besides, another FACT, newer TV's detect the Video Signal and do it that way. Maybe it doesnt like the signal voltage. I know for a FACT my Samsung, skips AV's that have no signal. i.e. nothing in my scart connections, then AV1 and 2 are missing off my selection menu.
Anemos, your links are confusing, cause they are all different.