The mask thing is something I've looked at a fair bit as it's law to wear one outside in Czech (the police even pinged some nudists for not wearing them the other day - god only knows why there were nudists in late March but there you are), and the general shortage of surgical masks has meant most people have simply made their own, which the evidence I've read to date suggests is little more effective than a placebo. Where things get potentially dangerous is, like in Czech, where people are so proud of their masks that they think they're bullet proof by wearing them, and don't do the social distancing, hand hygiene stuff. From speaking to the in-laws, there hasn't really been any guidance on even how to take them on and off properly, cleaning hands while doing so, all of that kind of thing.
