After the holiday weekend, Greg Lutes, owner of 3rd Cousin in Bernal Heights, got an email from Google that his fine dining restaurant had some new reviews. He clicked the link and saw a flood of uniformly bad one-star ratings left with no further comments.

Knowing this is the kind of thing that can sink a place over time, Lutes fired up an app to try to dispute the reviews, only to have his input denied. He was just starting to get suspicious that he was being targeted when an email arrived to his business account.

"Unfortunately, negative feedback about your establishment has been left by us," read a message from a person identified as Manas Agarwal. More "will appear in the future, one review a day," the email threatened, unless Lutes paid US$75 in the form of a Google play gift card, to be deposited in a Pay Pal account. "We sincerely apologise for our actions, and would not want to harm your business, but we have no other choice," the message concluded. "The fact is that we live in India and see no other way to survive."

Lutes, who has been in business for seven years, knew that scammers had found him. Then he recalled receiving earlier emails from mysterious companies offering to review negative ratings, for a fee. It all added up.

"It is basically extortion," he said. "They wanted me to pay them to make it stop."

Lutes checked his Instagram feed and saw that Kim Alter, owner of Nightbird on Gough Street, had posted a screen shot of the exact email he had received. The message has been received by at least dozen restaurants in the city, mostly high-end Michelin guide places. And it hasn't stopped there. The same scam appears to have hit restaurants in Chicago and other major dining cities this week. All have received a string of single-star ratings, the lowest possible on a scale of five stars, but no additional comments. It is basically the same scheme that hit high-end restaurants in 2018.

"Unfortunately, attempted scams are nothing new for San Francisco restaurants," said Mat Schuster, board president of the Golden Gate Restaurant Association. "This current attempt, which involves leaving negative Google reviews, is highly stressful, particularly as tourism has started to return."

It is doubly stressful for small mom-and-pop restaurants like Nightbird, which has 20 seats and needs to keep them filled. "Bad online reviews can close restaurants," said Alter. "If you look online and see a restaurant with one star you are not going to give them a chance."

By the time Alter had checked her Google page, she saw 10 one-star reviews for Nightbird, a seasonal California-style place with an average rating of 4.8 out of 5 on Google, and similarly high marks on OpenTable and Yelp. Alter started searching around and found that the low-rating scheme was only on Google. She also searched similar restaurants to hers in the city and found at least a dozen.

"I realised this is obviously a big scam," said Alter who has dealt with false reviews in the past. In her experience, the only way to combat them is to take the offensive, because the sites themselves will always side with the reviewer, she said. So Alter took to Twitter and linked to other restaurants that had been scammed, Acquerello, 3rd Cousin, Sons & Daughters, Marlena, Nari, Birdsong. It took off from there with retweets and more restaurants added to the thread. She started hearing from restaurants in Chicago and Houston. Not just restaurants. It has also hit bar owners and car dealers.

Alter has heard from seemingly everyone in the business, including people she didn't know from restaurants where she has never been, about the downpour of reviews. Strangely, she never heard from Google, which had been tagged in her Tweets and Instagram posts. Google did not respond to requests for comment from The Chronicle.

Twelve hours after Alter's partner, Ron Boyd, emailed Google, he got a form letter saying the incident was being investigated. That was the last he heard from the company. Just before midnight Tuesday, the bad reviews had been taken down. When Nightbird reopened on Wednesday, business was about average.

On Thursday morning, Alter warily checked the review sites to see if the scammers had followed through on the threat to do it daily. There was nothing.

"What is scary about this is that July is a slow month for restaurants in the city," she said. "I'm hoping they just leave us alone."

So is Melissa Perello, owner of Octavia in Pacific Heights, who was hit with half-a-dozen one-star reviews on Wednesday.

"We've issued complaints on Google, but as a restaurant owner we get the short end of the stick," Perello said. "There is not much we can do besides issue a complaint which does not merit a response."

She said business had not suffered at her 54-seat restaurant yet, but give it time.

"Negative reviews will knock down our overall rating," she said. "It affects people's perception of the restaurant."

Lutes also issued a complaint with Google through the business page support listing program. Within two days, he heard back from a human, which he took as a victory. He was asked to take screen shots of the negative reviews and email them to the representative. By Wednesday all of the negative reviews were gone, without comment or explanation. Over the four days that the bad reviews were active, his cumulative score dropped slightly but went back up to normal. It all happened too fast to discern whether the reviews caused his business to drop off, but he noted that this has been a slow week.

"I'm just waiting to see if they continue to try to target us," he said on Thursday. "Will these negative reviews stop or will this be something that I have to continue to try to fight?"

 - TNS