I am not sure I can help you here.

"... creation of chips, at the casino level, a "one man process" such that a single oblivious person could have created a "mistake" like this?"

Yes its possible. Anything is possible. At the Fiesta, I had almost total control of what went on the chips. But, my boss depended on me to keep him out of trouble.

"Is there an internal review & approval process of some kind by senior casino executives?"

There is at the Palms. My boss is a Director and our GM must sign off on the art.

"Does gaming have any role in determining trademark infringement issues on chip releases? Even as simple a role as asking, "do you have permission to use this?"?"

I was called once at the Fiesta and questioned on rights to pictures.

That said: I have always had my ducks in a row before I sent any art to Gaming. Paul-Son and Bud Jones before they merged would not produce chips without releases. Paul-Son got sued and lost back in the middle 90's over a picture used on a chip. Someone claimed they had a copywright on the picture after they saw the chips on the internet.

Chipco has questioned many different scans I have sent them. Everyone is leary of rights these days. I think it was a screw up.