If your instructor likes surfing their instagram account during lessons, get someone else.
It seems to me that FTUs could resolve this with two simple changes.
1. A poster in clear sight at the exit to the flight line, stating something like
“. Mobile phones are not to be used for non operational calls or texts during flight lessons”, and
2. As part of a student handbook (orientation) emphasize the FTU commitment with a money back guarantee to any student for their entire lesson if their instructor uses their phone for non operational purposes....
....and charge the cost back to the instructor..with zero tolerance for all the deflection excuses.
I am fairly certain the practice would end very quickly.
As to many of the other issues, an instructor code of conduct should be developed by all FTUs, though it is difficult to be to strict when the effective rate you are paying your instructors is about $8.00 for their time.
Most of the instructors today are young people with very little real work experience. And most of them will respond well if expectations are clearly laid out.
Not so much, if an FTU considers giving a longer syphon hose as a perk, and the directions to the local food bank.