Since this is beyond the boundaries of normal fraud, the rules may be a little different. No matter how you look at it, providing false information is fraud. But in this case a crime has been committed. Accepting bets from minors is a crime. I'm not sure if the crime is negated from the casino side since the casino was unaware of this transgression, but at this point we have the player admitting to the crime. In this case I would say it's a situation of: "Failure to adhere to these conditions will result in the user's account being closed and implementation of all other necessary measures."
In other words you are SOL. We can debate whether or not you should get any further funds from the casino until the cows come home - a law was broken and you need real legal advice.
Have you contacted the GRA? if not, why not?
Exactly, it is not "necessary" for them to grab the remaining funds not lost to the house in valid wagers. It is merely "desirable" for them to keep it as extra profit. They felt it "necessary" to return the original deposit made when under age, and yes, laws were broken THEN. Laws are not being broken NOW though, the current set of wagers are valid, and this is more a case of Bwin exercising their right who they do business with, in which case there is no justification for keeping the account balance once that decision has been made. The other bets were accepted in good faith by Bwin, from an adult, so they have a very good case here for keeping the money lost by the player.
The duff data was a single figure, the date of birth, and done by a minor to deceive the system so that he could play. As an adult, the player did nothing wrong. The wrong date of birth could not be corrected, and the player decided that now he was an adult, he was properly able to play in law, and Bwin were legally allowed to accept the bets.
He didn't even ask for the old deposit back, but took it's loss as a lesson learned as a minor. It may be "only $750", but the principle being applied by Bwin is that they could keep an unlimited amount on these grounds, way beyond what anyone in their right mind would consider reasonable. He could have deposited substantial sums as an adult, and played for a long time, Bwin could have seized tens of thousands in deposits that were not lost to the house, all over an indiscretion over $35 as a teenager.
If a player took such an aggressive advantage of a casino's mistake they would risk ending up in the evil player list. For a player, the right thing to do would be to tell the casino about the overpayment. The legally "necessary" thing to do would be to put aside the overpayment and wait for the casino to "prove the debt" by asking for it's return. If the casino do not make contact for 6 years (here in the UK), the debt can no longer be claimed, and the money legally, if not morally, then becomes the players' property.
Oddly, casinos have the exact same approach to dormant accounts, and often in much less than 6 years they consider the money is legally theirs if the player has not asked for it back.
Casinos should not be allowed to arbitrarily seize funds still sitting in a players' account just because they can. It has nothing to do with bets, it is money on deposit waiting to be wagered or withdrawn. If it's source is legitimate, it should be returned when the business relationship is ended by either party.
The player could have avoided this by being LESS honest, and breaking another term and making a new account as an adult.
By refusing to allow mediation, Bwin put themselves in the situation where the player cannot go about resolving the dispute in a more gentle manner. The GRA are hardly unbiased, they rule in favor of "spirit of" arguments from casinos, whereas a normal court would look strictly at the legal meaning of the terms and conditions, and the relevant laws of the country the player was in.
Taking them to court is more likely to be effective than going to the GRA. In the UK, for such small amounts there is no need to get a lawyer involved, the judge will look at both sides, and then apply consumer vs business law, which levels the playing field rather than allowing big business to use expensive lawyers to bully the customer into admitting defeat.
Betfair tried grabbing money back from players who took advantage of the terms and conditions, and then threatened those players who had moved the money out of reach with court action, only to back down when players said "bring it on" rather than return the money. Betfair even decided to keep DEPOSITS from players in some cases, and the whole mess ended up with them getting away with the cash grab, but ending up in the rogue pit.
If the player decides to try the courts, forget about just getting the balance back, argue that the case put forward by Bwin means that legally all bets, even as an adult, are void because of trying to sneak in under age. Bwin will have a hard job arguing it can pick and choose which bets stand, and which are void, purely to manipulate the player's balance to zero.
If he did take advice, the advice may not necessarily be to take action in Gibraltar in any case. More likely, it will be based on what action he could take on home turf, and based on domestic laws.
In the UK, when something is bought on credit, the bank becomes jointly liable for anything going wrong, and unlike the merchant, the bank is under UK jurisdiction, so could find itself liable even where the merchant argues it is not under it's own laws.
Banks recently fought this principle when it came to cross border transactions, arguing that the law only applied to goods and services bought within the UK. The banks lost the case, and now ALL transactions worldwide are covered.
A UK player in this situation could go down the joint liability route, and if they could show that keeping the money was illegal under UK law, could get the bank to pay up under the principle of joint liability. If this failed, a UK player could get a court judgement against the operator in this country, and then would be allowed to enforce it by any legal means they could find.
Operators know all about this, which is why they are usually keen to refund deposits at the time they make their final decision on a case. Claiming winnings is harder than claiming the return of your own money, and operators know that they can usually get away with confiscating winnings by saying all bets placed are considered void.