I went to my local grocery store shortly after 7am this morning. It opens at 6am but the first hour is reserved for seniors.
Somewhere between 60% to 70% of the customers were wearing something covering their mouth and nose. I was surprised at the number of people who were obviously wearing medical masks. They are virtually impossible to buy locally.
There were also quite a few who were wearing homemade improvisations. One woman even had a sparkly gold scarf wrapped around her face. I doubt it offered her much protection.
As a comparison, I was at the same store last week at approximately the same time, and there just a handful of folks wearing masks.
You want everyone protecting themselves in some way (even a homemade scarf) to reduce the odds of spreading and reduce the viral load if there is spreading.
Even the worst homemade mask is better than nothing, and in a group setting every little bit helps the group environment.
This is a classic case of “the perfect is the enemy of the good”.
They are hard to find now, but before this virus they were everywhere. Many people I know, including myself, have always had N95 masks on hand. If you work with or around wood, drywall, spraypaint, fiberglass insulation, do any sanding or home improvement/hobby work, these things are standard equipment. They are used extensively in non-medical industry and trades. Most people probably got them from Home Depot for use at home or from someone they know in a trade.
Speculation (obviously) on your part. Please re-read what the CDC recommendation regarding masks.