weird American birth certificate

My mother was born and given up for adoption in a state that seals adoption records for 80 years. We found her birth family because her birth certificate had her birth name crossed out with a single pen line and her adopted name written in above it. We surmised that her birth middle and last names were actually her birth mother's full name and since it was a rare last name we were easily able to find her in the 1930 census. This allowed us to locate her birth mother's still-living sister. All went well, but this was certainly an egregious violation of the state's adoption laws.