It might seem like a tenuous link, but AP News have reported that the US Supreme Court has taken action that might stop the dilution of the votes of black people in Alabama, and this has relevance not only to any Boundary Commission trying to creating cross-border constituencies including parts of Cornwall and Devon, but also may affect the election of future Police and Crime Commissioners for Cornwall and Devon.
In Alabama, congressional districts have been told to redraw boundaries because it is now recognised that constituencies that are drawn in such a way as to effectively disenfranchise black voters are unconstitutional. Jigging boundaries to make the votes of a particular group useless within a constituency is clearly objectionable, and this principle would also apply in the UK too, and to the Cornish.