Here’s a picture I received of the event:
On Shapiro’s podcast (yesterday), he further advocated other Jews do likewise — although he might have at least mentioned the existence of pertinent halachos (overheard).
Of course, Ben Shapiro may not suffice for everyone.
If you want primary sources, see this; history, see this; rabbinical endorsements, see this and this; analysis, see that. For fiery inspiration, see here. And we have a search option on this site.