We have had a series of irate parents at school. In each case the family decided to change a child's name long after the birth certificate was signed. Many times the reason given is I'm not with him (meaning the father) anymore. Or we thought person child was named after would give us money and they didn't so we changed the name. Other times it is we just felt like it.
Thing is they don't legally change the name. Now the teachers at my school let the kids put their new names on daily work but we are required by law to use the legal name on things like attendance, report cards, and standardized test. The parents still throw fits.
In S.A. black culture, the concept of naming and family is very fluid. Also, it's traditonal among some cultures (e.g. Zulu) to wait until you've had a child or two before getting married (the weddings are DAYS-long affairs, with cows being slaughtered, etc. Very lavish), so what usually happens is the child is given the mother's surname, plus usually a Zulu/Sotho/etc name and a "Western" name (usually English, but sometimes Afrikaans, even Russian, German, etc.). Some also have a nickname completely unrelated to their names. Then they don't actually USE the mother's name and are known by their father's surname! I often want to scream, "Just register the child in the dad's name already!!"
So you will have a child whose book labels all say, "Lucky Nkosi", but the classlist says, "Lehlohonolo Dube". Which is fine if you know the child, but if another teacher has to mark that child's test or something, they get very confused and don't know where to write the mark down.
Or, a parent must fill in a tear-off slip for an extra-mural. It has a space for the parent's name, a space for the child's name, and a space for the grade. So the parent will write, "I Pinky
parent of Snowy
in Grade 1
...", completely leaving out the surname and which Grade 1 class the child is in! So you look at all the Grade 1 classlists and can't find the child because Snowy is a nickname and the child's name is Lesedi or something. How are we supposed to know what is going on? Sometimes even the child's class teacher doesn't know the child responds to Snowy, and will say, "That child isn't in my class." Then, when the child is not signed up for that activity, you get an irate phone call from the parent demanding to know why.
We've had the opposite thing, too, where the child's legal name is Lesedi Kekana, but her parents call her Snowy and she uses her father's surname. And her parents NEVER told her what her legal name was, so the teacher is calling out, "Lesedi Kekana," and little Snowy sits there not knowing her own name!!
Parents seem to think teachers are psychic.