OK, so refs at lower levels would generally be local/regional, that I agree. Although his nationality will have nothing to do with it, as if he is a member of the association and lives in that area it would make no difference.
I've also spotted the gameplay effect of localised refs. They have different attributes, and depending on where you are playing you will have a local set of refs, but in cup matches where you may travel to a different area, the referee is likely to be different and one that is not so familiar with your team, and also may have quite different attributes from the refs you are used too.
(Finally see the point Ian.

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