To my non-expert mind, the approach here seems properly cautious. The notion that masks do not PREVENT infection in the wearer / inhalation of droplets in the bystander is used by some deniers to argue against wearing masks at all. Since the physical and emotional downsides of mask wearing would be greatly outweighed by the benefits of reducing spread and severity, there's little doubt that mask wearing should be mandated wherever possible (especially in public settings, e.g. schools, where social distancing is unlikely). Any advice that begins with "You don't have to wear a mask if..." should be questioned thoroughly.

The provisional findings described here would also indicate that combining masks with face shields would yield even greater benefits by further reducing droplet expulsion / inhalation.