Rules allow for that, you get repatriated when you move back.
1.0.3 Nationality of contestants
(a)
All contestants must be from the country/nation they are representing, and passports or other ID may be required as proof of this by the Contest Director, or the IJMC. People wishing to compete for National teams other than the country of their citizenship then the following rules (b) to (e) will apply:
(b)
They must apply in writing to the IJMC Council for permission.
(c)
They must have resided for two years in the country in whose team they wish to compete and must provide the IJMC with documentary proof of the period of residence.
(d)
They must obtain the agreement of their National Team to their membership of that country's team.
(e)
On returning to their country of citizenship an individual will immediately qualify for consideration for membership of that country's team, without the need for a period of residency. The IJMC has to be informed in writing of such changes in circumstances.