The relevant part from the concerning law is the following:
"Sec. 28-8. Gambling losses recoverable. (a) Any person who by gambling shall lose to any other person, any sum of money or thing of value, amounting to the sum of $50 or more and shall pay or deliver the same or any part thereof, may sue for and recover the money or other thing of value, so lost and paid or delivered, in a civil action against the winner thereof, with costs, in the circuit court.
(b) If within 6 months, such person who under the terms of Subsection 28-8(a) is entitled to initiate action to recover his losses does not in fact pursue his remedy, any person may initiate a civil action against the winner."
What this means, is that if someone loses money more than $50 gambling, it can be sued back. If the losers do not sue, anybody can. On this basis, losing against Illinois players seems highly profitable.
The winners who Mr Crespo sued are Illinois-based grinders, namely Andy Seth (BKice), Moshin Charania (chicagocards1), Faraz Jaka (the-toliet 0 ), Benjamin LeFew (chong94), Ravi Raghavan (govshark2), Tyler Reiman (puffinmypurp) and Kevin Saul (belowabove). They will have to turn up at court and defend themselves, however ridiculous the case seems to be.
The players already seeked PPA's (Poker Player Alliance) help, they assured the sued grinders of their increased attention to their cause.
