That's the bigger problem. A lot of people don't realize... all these people have to use the bathroom somewhere. Water fountains, passing by each other without 6 feet of distance on piers, not wearing masks, going to the same stores beforehand nearby to purchase supplies, kids playing with other kids, picking things up that strangers drop.
And let's not forget just the simple act of gathering people who haven't hung out to "go hang out for a beach day", so even a lot of these individual groups may be people from different households congregating.