Tail wheel,
It is very easy to change job descriptions and responsibilities. The persons on the visa rarely complain. I have seen parachute tandem masters who got a visa by being classed as "soccer coaches". There was a European helicopter pilot in Alice Springs (he had a bare CPL) who's visa said "tour guide".
There is nowhere near enough people to police the system. Please don't think that the "rules" stop the system being abused.