There are cameras EVERYWHERE in a casino. But the focus of a casino's security is to make sure that nobody cheats the casino out of a dime.
I've stayed in Las Vegas casino-hotels. For those of us too cheap to tip the staff, they supply large roll around carts to carry one's luggage up to their room. A customer could load a couple of steamer trunks on one which would hold all the supplies the shooter needed. It wouldn't raise an eyebrow.
The shooter could even have made use of the maid service by locking the trunks when he was out of the room. There were virtually no impediments to the shooter carrying out his plan and he would have been confident of that being true ahead of time.
Yes.
He would not have raised anybody’s attention, carrying his own stuff and not bothering anyone in the process.
Who would have even thought about a 64 year old white guy that looked like everyone’s grandfather would do what he did?
OTOH, if he had been a young Middle Eastern guy with bunch of extraneous luggage and an attitude.................