Drunken Gambling

I've never been to Vegas. But I don't think this is something I'd try. I've woken up mornings after nights out, and pulled a ATM receipt out of my pocket and was like "WHY DID I SPEND $50??" but $500,000? Jeepers.

Here's the story, according to CBS News:

A businessman who lost $500,000 on table games at a Las Vegas casino on Super Bowl weekend is arguing that he shouldn't have to pay because he was blackout drunk.
Southern California gambler Mark Johnston, 52, is suing the Downtown Grand for loaning him money and serving him drinks when he was visibly intoxicated.
Nevada law bars casinos from allowing obviously drunk patrons to gamble and from serving them comped drinks.
Johnston's attorney, Sean Lyttle, says the Grand, which opened last November in the old part of Las Vegas, intends to pursue Johnston for trying to shirk his gambling debts. Johnston put a stop-payment order on the markers, or casino credits, the Grand issued, and is also seeking damages from the Grand for sullying his name.
Johnston says he was thoroughly drunk during the hours he spent playing pai gow and blackjack at the Grand. His legal team plans to rely on eyewitness testimony and surveillance video to prove that he was visibly intoxicated.
Johnston lives in Ventura and made his fortune in car dealership and real estate ventures.
The Grand issued a statement saying it does not comment on pending litigation.
The state Gaming Control Board is investigating.

So let's gt this straight. His actions are excusable because he was drunk? What's to say his cold streak didn't cause him to have an extra cocktail or 12? I know what apparently Nevada law is supposed to prevent casinos from serving drunk patrons and allowing them to gamble, but shouldn't some of the onus be on Mr. Johnston here?