The other thing, unless you have a heap of children (by which time you generally don't need mushrooms anyway), how many mushies would get picked since, realistically, the kids would need line of sight to see the mushrooms. e.g. a kid staring at the cactus won't see a mushroom anywhere; the spot where they dance gives virtually no line of sight to the SE of the island, a little to the West, and very little to the SW - and all that assumes the child is not backing the mushroom in the first place