If I intervene with horrified shrieking when Leon plays with dirt and hoicks things up now, he is less likely to be positive about the garden later on, at an age when he can learn the difference between 'weed' and 'not-weed'. It is therefore worth sitting on my hands as dirt and plants go everywhere. (The volunteer broccoli raab from the satsuma tree pot may survive; the rocket certainly won't but there is plenty of rocket.)
A corollary: any potentially vulnerable plants that I really seriously care about are going to need some form of defence. I'm thinking in particular of my carefully-nursed autumn olive seedling, the sole survivor from a handful of seeds I stratified last winter and planted out in the spring, currently overwintering on the windowsill.
It was a lovely afternoon to be out in the garden, though. I planted peas by the fence, and Leon ate moss and dirt and threw soil around by the handful. Happy times.