Open secret in some areas. Anyway...
It was implied also on NRL 360 that there maybe others, well that was my take on the discussion.
The NRL need to start their education and testing regimes much earlier. When my son was playing juniors up here on the coast it was also suspected that a couple of the boys in the comp had an "unfair advantage". These boys played reps so testing rep players in the system would be a good start. That said one of the kids very strangely decided to take a year or so off reps and returned later a different body shape, puberty supposedly. He went on to play Harold Matthews.
Starting earlier and being high profile would be a deterrent.
Regards
Ross