For those unfamiliar with happy laps the event is designed to allow people to dip their toe in the water of track work in an relatively safe and enjoyable environment.
There are no rules regarding safety equipment etc (helmets not required, wear what you want) but as this is the case and this is a FUN event not a serious one there are rules governing track behaviour.
Passing is only allowed on the straights unless the car in front specifically waves you past, the car making the pass has the responsibility to do so safely and will be held accountable for anything that goes wrong. No dangerous driving or high risk stuff (don't dive under someone under brakes, no drifting, don't pass mid corner etc), speed is meant to be limited to "spirited" driving but who knows what that really means when you have R35's, E85 powered Evo's, built monsters like Sugar Daddy @500hp etc on track at the same time as almost stock daily driver R and V series Skylines. I was hitting around the 170kph mark at the kink at lakeside last time we did one of these to give you an idea of speed.
Common sense is the rule of the day. It is a brilliant event and loads of fun and at $30 for non SAuQld members including breakfast is as cheap a track experience as you will ever find.