Well it depends if you like to give or not since giving tip to anyone is not mandatory. If someone pressure you to do so and you are not comfortable with it then ignore them because its your money and you are the one who can decide if we want to keep your winnings. But if you can afford to give well this is also good because for sure people will remember the blessings you give and might you will also share the same vibes which if they win they also give tip to other people to.