This sounds as if it could slowly erode the whole "gendered surname" concept even in the origin countries (e.g. Russia)
If you can treat the gendered name simply as a grammatical construct, things are easy - and a "name" like "Elena Kuznetsov" would simply be a grammatical error and never occur as a real name.
However, now people from abroad visit the country or possibly even (re-)immigrate and suddenly you do have real-live "Elena Kuznetsovs" - in addition to the regular gendered names. This sounds pretty complicated to keep track of.
If you can treat the gendered name simply as a grammatical construct, things are easy - and a "name" like "Elena Kuznetsov" would simply be a grammatical error and never occur as a real name.
However, now people from abroad visit the country or possibly even (re-)immigrate and suddenly you do have real-live "Elena Kuznetsovs" - in addition to the regular gendered names. This sounds pretty complicated to keep track of.