One way to address mask hoarding in the Czech Republic has been a ban on selling any masks in the categories needed by medical personnel to anyone else than the state, which then bouth the remaining stocks a redistributed them to hospitals, first responders, etc. Similar thing has later been done also for some medicaments that looked promising for treating those seriusly sick with covid-19.

Doing this really seem like a much better way to handle the situation than giving a really really dangerous false advice like this.