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Not only roobet other casino can too.
In the case of "Slot" always be paid by the bet spin you spent with x maximum multiplier you can win, every casino needs to pay according to that's since the game slot was based 3rd parties service not from original game from them so the casino cannot decide the maximum $ payout they need to paid based the information of the game like how much maximum multiplier can we win on that game.
One of the examples "Money Train 2" the maximum you can win x50000, if someone can hit that with 20$(max bet) spin then the casino need to pay according to the multiplier 20$ x 50000 = 1.000.000$
Other casinos can have the same result who someone winning a big money more than a hundred thousand dollars because almost every casino using 3rd parties service slot providers.
I don't know if others casino can so that but I can only say what I'm sure about cause it something i have seen and it logical for every casino to pay the 3rd parties game according to the players multipliers but the game that bought this subject was crash which is the game operated by the house not the 3rd parties and there barely casino which can allow 200K plus multipliers.