I did not win any money (I wish!!!) 🙁
But – I know someone who did, and they received a check for the amount less 10%. When they asked why the deduction, they were told the school assumed they would WANT to donate maaser to them. They did not make an issue of it though they felt it had put them on the spot, but I was indignant because they support other institutions to whom they intended to give that maaser if they were to win (spread out to four places). I just wondered if this is typical.