Some parents still do. I once worked at an ear-piercing place/jewelry store. The youngest I ever did a baby was one week old. Her mother explained that she had had hers done as an infant, but her best friend didn't, and her friend was 12 when she was finally allowed to have it done. Her friend was terrified but wanted it done so badly she was crying beforehand, then didn't take good care of them - and wouldn't let her mother touch them, and they got painfully infected.
"I don't want me daughter to go through that," she said. At this age, I can be the one in change of keeping her ears clean, just like the rest of her, and as ALL the women in the family have pierced ears, I know she will want them, too."
The baby was sound asleep, and her mom held her facing forward. The baby's head was tilted on one side, I did that ear, and she just squeaked, didn't even wake up, and tilted her own head the other way. Done!
But is the stupid own who pierced the kitten's scalp gonna be there its whole life to make sure the "earring" is adjusted in length as the kitten grows?
Richard, I think that notching the ear of a feral in a TNR program is actually a good thing. It is done while the cat is "under" for the spay/neuter anyway. And for truly feral kitties, it spares them being caught again and again just to find out its already a "fixed" kitty.