My girlfriend has a 5 year old son. On his birth cert the father is listed as unknown. She received advice to add my name as the boy's birth cert as his father. Then in the case of us parting ways, I could contest the paternity and be removed which she says would eliminate any future financial obligations.

Is it that easy? Would I really have no future obligations to her for his support? We live in Georgia.

Nope not that easy. In fact you could go to jail for fraud. A birth certificate is a legal document. Also in some states it can't be overturned after a very short period. Why doesn't she go to court for child support against the birth father and get his name on it as it should be ?