As I understand it, the lack of a legal requirement for flying training has caused no particular problem - for the simple reason that unlike a normal aeroplane (where you just open the throttle) it's very hard to get airborne without being properly taught how. That tends to force any prospective paramotor pilot to get some proper training anyhow, and once a school has them they tend to get taught properly and completely.
However, the lack of air-law knowledge has caused more than a few problems (I know of two GA airfields which briefly gave permission for paramotor flying until they got seriously p****d off with a complete lack of acceptance of runway and circuit practices.
G