So I am currently in Las Vegas, ironically staying at the MGM. When we checked in on Sunday, the check in line was LONG. All our credit cards were denied. Which ticks me off because they KNEW about the attack apparently since Friday evening, but still, knowing our CC's would be denied, went through the motions. All the snack shops were cash only, and yeah, about half the slots are down.
Monday we learned about the hack. Luckily we brought cash, but most people didn't.
We went to the Titanic exhibit, and had to pay with cash. All the non-casino restaurants and fast food in the courts all can take cards.
I talked to a lady who works in a shop, and she said there was a concert Friday night that had to be cancelled because the machines didn't recognize any of the tickets. It rejected all of them. Since then, it went out like a spider web from there, so she said "they" think that's where it started.

It has just spread further and further. She had heard that other casinos are starting to have problems also, so I'm sure the hackers are emboldened. I am wondering if they will take down the whole strip. That would be funny!

I think the most I've noticed is gambling machines down, having to pay cash, and the very, VERY long lines, snaking almost through the casinos, for check in. Some of the hotels are giving guests in line a can of beer or a bottle of water. People have been patient, and the employees are nice.

We have had no problems with room keys or anything else. It's been a nice stay. they finally got some big signs around the casino apologizing for the downed machines and problems. Since we aren't here for gambling, we are having a good laugh at it all.