At the park today with dd1. The park is driving distance from our house and much bigger than local parks. It has a huge wooden climbing structure with slides etc. The structure has signs all over it saying that it is not suitable for under 8s which is reasonable judging by the size of it. Dd1 loves it (she's 9). However, there were some children on there who didn't look older than 2. They were struggling to walk around the grass nearby let alone manage the challenges of the equipment.
Some parents were sat miles away, whilst others were encouraging these toddlers onwards (and upwards). Bigger kids were having to queue in some pretty unsafe spots as these children clearly couldn't cope.
I just think if it says 8 and over and your child is way less than that then you shouldn't be on it. The park has ample provision for little ones which I don't let my 9 year old go on.