While basically I like this a bit (though as I say not sure of Grandparent rule) , I can understand why many 2nd tier countries are against, as I keep saying it not just about Islands (which is all us lot in SH seem to think about), but Georgia, Romania etc, do we think it great idea for some of their top players to take a test cap to help out France etc etc and then just come back late in their career? Whatever we think I repeat we have to think of all the world not just Island players! Uruguay could very well suffer the same problems with a lot of their players making a living in Argentina!
I repeat I do like the idea of a player who has played less than say 10 tests being able to swap back after a stand down, but I do also think it not that simple and we have to worry about whole world not just SH!
Those same circumstances that exist for the PI nations aren't remotely close to existing for Georgia and Romania etc.
Georgia is a country of 3.7m people and there are 12k or so Georgians living in France. I highly doubt that there is a significant portion of the Georgian population with French grandparents. They are more likely to lose players to the residency rule (which has already been extended from 3 years to 5 years to make qualification more difficult).
Uruguay is a better example and there are plenty of Uruguayans who have emigrated to Argentina but likewise, the numbers are minuscule as a percentage of their population compared to the PI nations.
I genuinely think the Pacific Islands are a special case because they both produce a large proportion of the world's professional players and have an unbelievably large percentage of their people living away from the islands because the economic opportunities available at home are so limited.
If anything the parent/grandparent rule helps out tier 2 nations because good rugby players in rugby nations who aren't close to making their tier 1 test team opt to represent that other team because they want a chance to play test rugby and go to a RWC. Australians such as Greg Peterson and James Hilterbrand for the USA and Adam Byrnes for Russia come to mind.