My question would be: what is the role of the GM and what is the appropriate scope of "ruling not rules"?
My memories of playing as a child/pre-teen were that there were a lot of arguments, because the game (basic) leaves a lot to interpretation, and 11 year olds like to argue. But as an adult, my players (who are also my friends) come to the table wanting to have fun, not argue.
In this sense, I think ruling not rules--that is, a high-trust game--works best when the GM is not the totally neutral "referee," but has a little bit of the "be a fan of the PCs" in them. Basically, it's more fun for everyone when what the PCs try to do could plausibly work, depending on the dice. Both the 1e "referee" gm and the 3e rules over rulings style creates, imo, a possibly adversarial game in a way that is not fun.