Porters are well paid - by PNG standards really well paid - and they love doing the work. If you pay them even more at the end of a successful trek, you will probably confirm their view that every white man is a walking wallet. Yes, you have lots of money and they have hardly any... that's the way it is.

And keep in mind that PNG is mostly free of people constantly hassling for money. This is a good feature to maintain. Giving money away may encourage a belief in entitlement to 'always a bit more'.

Think carefully. It's a complicated issue.