Nah - taking out a loan and a marker are different.
The marker is not taking out a loan and saying you will pay it back.
The marker is saying "I have $$$ amount of dollars - this is the amount I wish to gamble. Instead of going back and forth and withdrawing money etc etc - I'm declaring this much money to you the casino. I'm giving you permission to withdraw this money from my account in a lump sum."
If you pay for something worth enough with money you don't have - it will be considered a theft.
You think if you write a check for some jewels and disappear, they just send you collection letters? Everyone would do it
He essentially stole money from the casino. If it's enough to cross the threshold to a felony, he's gonna get arrested.