The things I got up to as a kid would cause pandemonium these day, I helped build the estate my parents still live on before I started school, would get up in the morning, Mom would do me a packed lunch, would cross the road to the builders mess hut, put my sarnies on the table at ‘my’ seat then spend the day with 2 Irish builders (and yes they were called Paddy and Murphy!!), they would let me drive the dumper truck, was up and down the ladder on to the scaffolding laying bricks with them, plastering the walls, even had red hot tarmac in my Tonka dump truck to help lay the road etc and the only time my Mom got a little upset was when we went swimming in the lake one afternoon as it was too hot to work!! These days those 2 builders would probably be accused of being nonces and the building site closed down due to a 4yr old working there, unqualified and unpaid!! When the builders left I packed my bag to go with them lol. In hindsight it was totally irresponsible by all parties but at the same time the dangers were always managed ie I was given leather gloves when tarmaccing, helped up and down the ladder and always someone with me when on the scaffold.
Would I let my kids do the same, probably not but would certainly think about it.