My 3.5 year old would be the one scared to go on that equipment as she gets nervous around things that open.
And why? Not because I'm a helicopter parent but because of the time she fell off such play equipment as I was one of those mums who was sitting chatting with a friend.
I'm not so much blaming myself or saying I was irresponsible or negligent but I don't think it should be a blanket you're either a helicopter parent or irresponsible if you aren't, but it depends on the child as to what is appropriate.
Some kids need helicopter parents, some need free range. Let's not judge parents either way