Many kids are looked after by maids, grandparents or older siblings. Abuse can very well happen in these situations. It is important to let you kids get in the habit of reporting ALL bad touch to you.
You can decide if that touch was really abuse. If a person is touching your kid without intention of abuse but the kid does not like it then it is better to tell that person to stop touching your kid in that way. This is very relevant with grandparents and maids.