LCD TV's defaulting to analog?

[Chad Hauris]

I was at a pizza parlor in Midland today where they had flat panel 16 X 9 sets set up on the walls. They were tuned to local channels and displaying what appeared to be a weak analog signal from an antenna (grainy with some snow and interference lines)
Do some of these sets default to the analog signal if the digital is too weak? Or were they maybe just not set up to receive the digital signal?
All of the stations here are transmitting digital so there should be a digital signal available. The TV transmitters are probably 15-30 miles away from the pizza shop.