Very interesting! I've been checking the "my offers" part of the website, and Las Vegas has totally disappeared there -no room offers, no food, no entertainment, no nothing!
I plugged in the dates of my July trip, and it was a different story. Flamingo was lowest at $168 for 5 days, next was Ballys at $256, Rio at $414 and Caesars was $839 for classic room or $1493 for Palace of Augustus tower. Harrahs and Paris were unavailable that week but still showed prices of $305/$545.
I guess it never hurts to ask - even on the website.
