What's in a name?

Two days ago I was at work and received a call from a patron wanting to sign her daughter up for storytime. It's a family we know and have served for the last several years, so even though they always struck as a little bit unconventional, nothing prepared me for what the conversation would hold. I was almost finished with the sign up when I checked to make sure I had the correct spelling of the little girl's name. I usually put up name tags for all the kids each session. It helps them to practice name recognition. Anyhow, as I was confirming the spelling, the mother informed that her daughter only answered to "Big Sister" at the present time and that she thought I should put "Big Sister" on the nametag. So that's what I did. I wasn't going to argue with her, though I have my own thoughts on the subject. Mostly, what's going to happen to this little girl when she is 40? Is she still going to want to be called "Big Sister?" I thought it was funny. Definitely gave me a giggle. Seriously though, what is wrong with people? A nickname is one thing...poor Sarah has been "Sarah-Beara" for as long as I can remember and my brother calls me "Nosey-Rosey" when he wants to irritate me. I know we all have little nicknames like that, but I wouldn't go around telling people that was my given name, would you?