A class action lawsuit filed Monday in Middlesex County Superior Court claims that Encore Boston Harbor withheld money to patrons who reported winnings in blackjack and at the slot machines, violating state gaming rules and regulations.

The lawsuit, filed on behalf of A. Richard Schuster of New York, claims that Encore made the visitor play by traditional blackjack rules, where winnings should be paid out at odds of 3 to 2, but only paid him his winnings at odds of 6 to 5, which are typically reserved for a different style of blackjack.

When a player is dealt a “blackjack," or two cards that add up to 21, someone playing traditional blackjack who bets $50 should win $75. Under the “6 to 5 variation,” that person would win $60.

Schuster also alleges the casino withheld players’ money on slot machine, rounding down to the whole dollar when a player cashes out.

The lawsuit alleges that Encore "paid its customers odds of 6 to 5 when a player is dealt a ‘blackjack’ when Massachusetts law clearly and unambiguously states that a player who is dealt a 'blackjack’ ‘shall be paid at odds of 3 to 2.’

According to Massachusetts game rules, winning bets pay out 1 to 1 unless the player is dealt a “blackjack," in which case the winning bets is paid out at odds of 3 to 2 for standard blackjack or odds of 6 to 5 for the “6 to 5 blackjack variation,” which is 1.2 times the original wager. The odds are typically posted at each table.

Wynn Resorts spokesman Michael Weaver said in a statement that “Encore Boston Harbor follows the Massachusetts Gaming Commission’s regulations for blackjack payouts,” referring a reporter to the Massachusetts regulations.

In a statement to MassLive, the commission said, “We are aware of the lawsuit and are reviewing its contents to determine next steps.”

Schuster visited the Everett casino Thursday and played several table games, including blackjack, according to the lawsuit. He claimed he played at tables on the main floor that should have paid out winnings at odds of 3 to 2 but only received winnings at odds of 6 to 5 after being dealt several blackjacks.

Schuster also claimed he played the slots and was only paid out in whole dollar amounts when he tried to redeemed his tickets with the balance owed to him.

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The lawsuit describes several differences between traditional blackjack and the variation: “6 to 5” blackjack is typically played with a single deck or two stacked decks, while standard blackjack can involve a “shoe” of up to eight decks.

The plaintiff also argues that standard blackjack requires a dealer to hand out the cards face up without letting the players touch the cards, while the variation involves more decks and has the cards dealt out to the player facedown, letting the player pick up the cards evaluate them.

The game rules on the commission’s website do outline a separate procedure for the “6 to 5 blackjack variation.” The rules state that each player will be dealt two cards face down and that each player may use one hand to “pick up and evaluate the two cards dealt to him or her.”

It is unclear whether the table Schuster played listed the odds as 6 to 5 or 3 to 2. The lawsuit did not elaborate on the signage at Schuster’s table.

Those differences in odds may seem small, but they can lead to major differences in pay. The lawsuit estimates that if players are shortchanged, they could lose an estimated $35.60 per hour on $50 wagers. That number could add up to $85,440 a day and $30 million a year at Encore’s 20 tables.

And that’s only for $50 at a casino known for attracting high rollers who might bet hundreds or thousands in a game.

When slots players cash out, their balance is printed on a ticket that must be redeemed at a machine. Schuster claimed the machines only pay out whole dollar amounts, accusing Encore of rounding down and pocketing any remaining change that belongs to the player for itself.

Other Encore visitors who played slots say they were paid whole dollar amounts but received a separate voucher for the leftover change that would need to be redeemed at another part of the casino. Bill Dorazio Sr., a North Tewksbury resident who has played slots multiple times, told MassLive he has had “not a problem." Another visitor told MassLive she never had a problem getting her winnings redeemed.

Wynn Resorts saw its shares of ups and downs in the year leading up to the $2.6 billion casino’s opening, following founder Steve Wynn’s resignation amid sexual misconduct allegations. After a lengthy suitability process, Encore was fined $35 million but ultimately was allowed to keep its casino license.

Encore opened June 23, drawing thousands that Sunday morning alone. The Everett casino generated $16.7 million in gross gaming revenue in its first week, according to the commission’s monthly revenue report published Monday. Table games generated $7.6 million — nearly half of the total revenue — with the remaining $9.1 million coming from slots.

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