We were at WDW from Feb 1-6 last year, just DH and I, and we saw people turned away at every restaurant we went to, except the California Grill. No one asked while we were waiting to go upstairs, but then again, it's not really a place you would walk up to.
People turned away from Boma (opening time, 5:00, I think?), Teppanyaki (late lunch, and they were not taking walkups the rest of the day), and the Coral Reef (early dinner, 4:30 or 5).