I worked for a major helicopter operator in PNG on a tourist visa for over a year: immigration at border check-point knows what's going. They see a guy coming in and going out every month for over a year. One day they said no, calls were made, I was let in and had my work permit by the end of the week.
I don't know how guys can be doing a 5 month hitch on a tourist visa without at least going out on a visa run.
And about inexperienced guys getting caught out in the PNG environment. Plenty of experienced guys get caught out as well...and plenty of PNG experienced guys get caught out. 6 pilot colleagues of mine - all highly experienced - have met their demise in a helicopter prang in PNG during my time there.
3000 hours helicopter experience used to be the minimum even to get looked at for a first time PNG pilot applicant. I know that number has been reducing, as low as 1200 hours for some now.