Such scenes have been replicated across the country. In South Lake Tahoe, California, the mayor told visitors to stay away. In the Hamptons on Long Island, some New Yorkers tried to heat their pools as markets ran out of food because they didn't anticipate so many shoppers, and hospital workers worried about being able to manage an influx of patients.

Rhode Island's National Guard and state police are stopping drivers with New York license plates and going door to door to find people who recently traveled from New York to second homes, demanding that they self-quarantine for 14 days.

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Longstanding tensions in many vacation communities seem to be boiling over as everyone tries to figure out how to keep themselves, their families and their communities safe from a virus that, while ostensibly indiscriminate, is more easily fought by those with wealth and resources than by those without.

The Edgartown Meat and Fish Market on the eastern shore of Martha's Vineyard is still open. Owner Sean Ready saw an "influx" of seasonal residents about two weeks ago. People can shuffle into his market, stand 6 feet from the counter and buy fresh food. He also offers curbside pickup and is doing all he can to keep his staff safe.

"We're happy to be open and continue to pay our employees," Ready said. Business has "certainly gotten busier" than usual in March, but that won't mean much if he doesn't have his usual summer business.

Ready, who has been a permanent resident for 10 years, understands why people are coming to the island.

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"If I was in their position and I had a family of four in downtown New York City and I had a house in Edgartown, I would probably want to be in Edgartown, as well," Ready said.

Still, he has concerns. "It is relevant and appropriate for the hospital and local community to look at what resources we have and to say we would be overwhelmed if it was just our year-round population. Let alone the seasonal residents."

COVID-19 triage tents in front of Martha's Vineyard Hospital on Tuesday. The facility has 25 beds and seven ventilators. Kayana Szymczak / for NBC News

In a livestream for the community, Denise Schepici, CEO of Martha's Vineyard Hospital, painted a stark picture of what an outbreak on the island would look like.

"We have limited beds and limited medical supplies," she said. "We don't have enough staff to care for you during a surge of coronavirus."

Schepici said the hospital, which declined to comment, is "very concerned about passengers coming over on the steam ship" that carries people between mainland Massachusetts and the island. If a surge occurs, Schepici said, the island "would not be able to handle it." It would take only nine serious hospitalizations for the island to be overwhelmed — and it already has eight cases.

That's why Dylan Fernandes, the state representative for Martha's Vineyard and Nantucket, asked seasonal residents to stay away.

"We don't think it's too much of a sacrifice to request people not to come open their beach house so that our local hospitals aren't completely overrun," he said.

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Of course, Fernandes said, people have a right to stay in their own homes, but in a global pandemic, they ought to consider the scant resources.

"I just don't know that people that don't live on the island and want to come over to their beach house or summer home are fully aware that they're going to be coming to a health care desert," he said.

Fabio Junior Barros, an island resident whose wife was tested for COVID-19 at the hospital Tuesday and is awaiting results, agrees. "The people who have summer houses here need to know the hospital will not be able to attend everyone," he said.

Fabio Junior Barros stands at the entrance to COVID-19 triage tents Tuesday in front of Martha's Vineyard Hospital. He came to the hospital with his wife, who had a fever, and was waiting to be tested for the coronavirus. Kayana Szymczak / for NBC News

Martha's Vineyard tried to get ahead of the state, enacting stricter stay-at-home orders and banning construction, even though Gov. Charlie Baker deemed it an "essential service."

But many of the Vineyard's 10,000-plus summer homes are filled. The Steamship Authority saw more license plates from New York and New Jersey than usual in March, and local government officials estimate that the island's off-season population has doubled in the past few weeks. Airbnbs quickly went off the market, rented by people looking for places to ride out the pandemic.

As people argue online about whether seasonal residents should be there, tensions have spilled into real life. One seasonal resident told The Martha's Vineyard Times that her son was refused an oil change when the mechanic saw his New York plates.

In some areas, residents have blocked people from entering their communities. Residents of Vinalhaven Island off Maine cut down a tree and placed it across a road to try to forcibly quarantine a group of out-of-towners. Residents on Noirmoutier, in the Atlantic Ocean off the coast of France, wanted to close a bridge to prevent second-home owners from coming, but national authorities said it was illegal.

The decision to flee to vacation homes amid a pandemic has also laid bare class tensions long seen in these communities. While some Vineyard residents are out of work and without health insurance in a community that's been suffering from the opioid epidemic, college students sent home from school early can be seen milling around the streets, passing the time at their parents' second homes.