^^^^
Gosh! I've had my GTI for 7 years, driven 100,000 miles and never noticed any buttons low down on the B-pillar!
Since fitting Climair wind n rain deflectors (I can strongly recommend them), I sometimes leave all 4 windows lowered a fraction but never below the bottom edge of each ClimAir. You can't easily see if the window is lowered at all.
I only ever do this if it's a very hot day and I'm staying in sight of my car.
I expect that an insurance company would say that even if the doors were locked, if you left any windows open, even a fraction, your claim against your car theft would become invalid.