Safeguarding and volunteer checks
It's best practice for PTAs to have a set of safeguarding procedures in place, and guidelines for your volunteers to follow at events, e.g. a lost children policy for school fairs; toilet visits at discos. These can be developed with guidance from the school. You may also need to consider when volunteers need DBS checks (England and Wales, formerly known as CRB checks) or NI Access checks (Northern Ireland).
PTAs have a duty of care to consider the safety and well-being of children and vulnerable adults, so make sure this is considered when risk assessing your event.