I change IPs and have not had problems... (home/school, school is somewhat dynamic IP)
For other countries, the main problem is their ISPs have few actual IPs... but since you are using a 3G device you are getting internet provided by your cell phone company so it should not use that country's ISPs
A safe thing to do is if you have a desktop machine at home, enable remote desktop, and use a browser on that machine to access cybernations.