@MontereyJack,
one of our larger populations of concern are the Amish. They've recently given up "staying at home on all Sundays". They have church services at selected homes every other Sunday. Starting on Easter, the "House Amish" as they are better know, decided to resume their bi-weekly services. They had two services since Easter and we notice an uptick in infection .
The Amish have close contact, high fellowship services that include church, and follow with two meals and lotsa close order talk and parlor games. A normal church sunday could possible infect an entire parish (which is usually topped at about 250 or so members.