Maybe not in a communal play situation, where the toys/ treats etc are not theirs alone to begin with. But to demand child A to give up their toy/ treat/ turn to child B because 'sharing is caring' makes no sense to me. I, as an adult, am not obligated to let my friends borrow my shit, so it's not a life 'skill' that follows you through life. Also, it feeds into the entitlement that I've seen displayed by children (and adults tbh) who insist that they are owed a turn/ a stake just because another individual has something nice they like. I think children should be encouraged to be kind to others, and explained to why exactly its nice to hospitable, but not forced to if they don't want to. Your property is your own and it should be respected.