Couldn't agree more with you. Thing is, the warning lights are effectively 'latching' switches - any fault, no matter how transitory in nature and on they go and on they stay.
If the car is scanned for DTC's and none are found, then after a reset if it happens again you've got a problem and then things need to be phyically checked.
I was in this situation with the oil warning lamp on my last A2 - in the end, they replaced the oil sensor switch, the section of loom between it and the dash, and the dash itself - just to make sure!
It did cure the problem however, but with brakes, it is firstly a more involved process of checking and replacing and secondly infinitely more important in safety terms.
WAS : A2 TDI SE 2001 Ebony Black Pearl (The Little Tank!)
NOW : A2 TDi 90 Sport, OpenSky, winter pack, ISOfix, all-round fogs, climate control, all-round electric windows, Blaupunkt DAB54, genuine HID xenons and red leather! Not to mention CCC Tech chipping (118bhp), all round tinting and retro-fitted cruise control.(The NEW Tank). Black headlining and retro-fit Bose coming soon!!!