I just pop my phone on the photo-copier. Damp postit on the ADF, auto-scrolls the screen on each cycle.

You are joking right? If not, I'd kill for a video of this setup working.

Sadly I am. Although I'm idly just considering putting a magnet on the scan-head of a flatbed scanner. Could then just use tasker to detect the passing of the magnet as a 'page-down' scroll on the screen.

the "adb shell input" command as used in the linked article would be simpler.

You can either use root access or disassemble the app, remove the flag, and then assemble it again. Impossible to do if the app uses SafetyNet though.