The Toa squad is made up form players who qualify for Samoa through their parents or grandparents and are either Kiwis or Aussies (or there is Frank Pritchard, born in Liverpool Hospital an he played for NZ and Samoa!!) and they only pledge allegiance to Samoa when they do not make the NZ or Aus squads. There is no financial incentive when they play for Samoa, but there is a strong commitment to the jersey. No matter where a Samoan is born, there is a strong cultural connection to Samoa. From memory in the Tongan team, there were two Tongan born players - Kata and Hurrell - the rest were in similar situations to Samoa.
I would like for all players who play in the NRL to be eligible for SOO, then able to play internationals for the island countries. This is a different debate though.