I, like many here, use a syphon to refresh / replace my power steering fluid. I got to thinking (which can sometimes lead to strange ideas) why can't I do the same with the brake fluid? Syphon from the reservoir and replace with OEM brake fluid? Of course, you can't empty every drop from the reservoir lest you make an air bubble in the line. But you can do 90% of the reservoir and top off to the 'full' mark with fresh fluid every week or so until the reservoir has nice, clear fluid again.
Have I gone mad or will this work?

I think in theory it'll work...but you should still do a brake bleed at each caliper IMO.

Buy a "mighty vac" and suck the old fluid through the fitting on each brake caliper starting with the right rear, then left rear, then front right and lastly, front left. Open the cap on the master cylinder reservoir and add fluid as you go ensuring the reservoir never gets empty. Use the vac at each caliper until the fluid that is sucked through is clear (not yellow or cloudy). Just putting new fluid in the reservoir won't work. The new fluid will never get all the way through the lines to the calipers without bleeding as detailed above.

aaaa HAA! That didn't occur to me. The power steering is a circulating system so all of the fluid goes from the reservoir and through the whole system, then back into the reservoir. I'm not sure that freshening the brake fluid in the reservoir will actually cause fresher fluid everywhere else. I reckon my syphoning trick might not be an effective way to keep the brake fluid in top shape. Is it possible that old dirty fluid might remain in the calipers unless they are bled?

Yes - exactly.

Thanks as always for the advice ! Seemed to easy to be good. I'll just have the dealer change the fluid with my next brake job. I can't be bothered with a vacuum, the mess, and disposal of the old fluid. Last time my dealer did it, they reduced the fees since I was having brakes done at the same time - charged my about $100 extra if I remember right.
When next you apply for a job, tell the rep that you saved a foreigner from a horrible mishap!