Makeshift masks don't necessarily even help in that situation, become a liability when contaminated, and putting it on then removing it causes additional risk.
Don't worry, people aren't morons and have been using masks in Japan and other countries for decades just fine.
Yes, masks can hold contaminated droplets --that's their purpose. When people don't use masks on the other hand, those droplets that would have remained on the mask now end up everywhere else, and now you have a far more spread vectors with basically everything being potentially contaminated.
Using a mask ensures that a lesser percentage of your contaminated droplets end up in other places.
First, masks work better when both sides use them. In Japan, healthy people wear masks as well during flu seasons because it makes it offers better protection than wearing nothing.
Second, in the specific context of COVID-19, how do you know they're healthy? That's the key, because asymptomatic cases are estimated to be the main driver of this pandemic by far. And it's only worsened by the fact that only few tests are available.
> Third, of course masks work — maybe not perfectly and not all to the same degree, but they provide some protection. Their use has always been advised as part of the standard response to being around infected people, especially for people who may be vulnerable.
Yes, they would. The healthcare worker may already be sick, and are regularly closely interacting with people that have compromised immune systems. An illness that wouldn't slow down a nurse may kill a patient.