Suppose its the same for all squads, when you consider other sports its been very common place for players to be lured across. NZ/Aus and the ongoing back and forth with Tonga/Fiji/Samoa, English footballers with African heritage playing for countries of their parents/grandparents or that period English cricket had a fair few South Africans in it.
Just have to rely on that players like Smith want to play for England and aren't afraid of the contest for a starting/squad spot.
Also noticed this link we originally posted, stated that Scotland had 27 foreign born players in the squad without these latest additions. Full list is attached here for all 6 nations squads:
https://www.americasrugbynews.com/2022/02/02/foreign-born-produced-players-in-2022-six-nations/