It sounds like people see this as a superfluous regulation. It actually has a very clear purpose. Fluid colour is meant to indicate compatibility. DOT 3, 4, and 5.1 must be clear to amber by regulation. DOT 5.0 which is not compatible and must not be mixed due to composition must be purple. Hydraulic mineral oil must be green. Anybody installing a dark blue fluid that isn't 5.0 is risking that future service work could include topping up with 5.0 with dangerous consequences. Same the other way around, if non silicon fluid is installed in a vehicle that has 5.0 in it.

I always thought the marketing department at ATE was going after those who wanted 'racing' fluid by offering a product that looked like DOT 5.

Clean brake fluid looks clean and you can tell when it comes out the bleed screw. I've always used clear fluid when flushing.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue