It absolutely is disclosed before you purchase. They aren't scamming anyone.
http://ridemax.com/order.php
We’re closed on Sundays
We've made the personal decision to not gather wait time statistics on Sunday, and you won't be able to select Sunday as your "visit date" in RideMax. We do, however, offer advice for using RideMax to map out a Sunday visit in our "Tips & Hints" pages, and many customers have reported success using this advice to plan a Sunday visit.
I see your quote but were you trying to post a response also?