I once was at an indoor play area (in a mall) and this little 3? Year old girl was crying, holding her crutch (obviously needed to go to the loo). I looked around, no parent. I asked the little girl if her mum was in the cafe just up from the play area and the little girl said yes (cafe was enclosed with a door, you couldn't see the play area from the cafe). I said let's go find your mum and without touching the girl led her to the cafe. I yelled "anyone know this kid" and there was a mum at a table having coffee with her friends. I politely as I could (because her kid was there) read her the riot act.