It may have to do with AT&T's reception in the parks...?
I have an iPhone and i have noticed terrible service in select places in the park.... Specifically Coke Corner, and other parts of Main Street...
...and rides... but that doesn't really count.
I would love for this to come to the iPhone though.
I currently have WaitWatchers for DL and DCA and it's a pain in the butt. It's one of those peer update Apps... and it's rarely accurate.