Silly sign

Bit of an emergency blip today. Work and then parents night. Thought I had time to fit in a quick swim but obviously didn't as Ross was half way down the street heading for football before I'd even parked the car!

I see this sign every time I go swimming and it amuses me. So a 17 yr old can drive, get married, have children but can't put a child in a playpen?

edit 1: I also saw one the other day that said children had to be supervised by a responsible adult when on a climbing frame but I couldn't find one.

edit 2: just noticed the size of the child in the playpen!!