All Seven Stars (and I am sure Diamond players too) have a credit card on file with the casino (Caesars).

I personally rarely arrive before 6pm but my host always puts on my reservation that I am likely to arrive at 12 midnight or sometimes later. Frankly, when I drive from LA, I usually don't leave till about 8pm after traffic.

In all honesty, I wonder just how many people are "no shows" on comped rooms and failed to talk to their host? I think this is much ado about nada.