For anyone who missed it, this has been discussed at length at
WOL:
http://mb.winneronline.com/showthread.html?t=23026
It's my opinion, and also that of webmasters I rate, that this player should at the very least be given a 50 / 50 payment of her winnings. She did sign up underage according to the Vegas Laws, but the casino accepted fully SEVENTEEN deposits and THREE winnings payouts until she hit a big one...then it was sorry, you're SOL and here's your deposits back.
She's out £10,000 GBP. She is entitled to a 50/50 split at the very least, and a payment of £5000 GBP.
It's also worth noting that online gambling is ILLEGAL in Nevada - yet Microgaming casinos continue to offer "Nevada" as an available state in the signup process. Make of that what you will - I shan't be risking a tarring and feathering here by drawing any conclusions.