This may seem like a trivial thing but I can tell you, it is not. Deep bites are responsible for many TMJ inflammations due to anterior misguidance via anterior prematurities that distalize the mandible. When you observe deep bites developing, tell the parents about prevention and how you intend to intervene in this developmental disturbance as well as the benefits to the child. There are different techniques to do this. You need an understanding of FJO and growth and development.
Simple Hawley with anterior bite plane will work.
Remember that a child can be uncomfortable or even hurting but not understand why. Because the parent "cannot see anything wrong" the complaint gets dismissed. Eventually the child stops complaining because the pain is not constant. When he/she is hurting, there is no apparent problem. We have to train ourselves to be aware of the possible problems associated with deep bites. Most of the time, there are none, only the potential.