Are My Local Krogers Blocking EDGE Data?

Since getting my iPhone, I’ve visited two Kroger stores near my house and in both stores I was unable to access the Internet over the EDGE network. In both stores I had 5 bars of signal, and in both stores I was able to place calls, so it wasn’t a signal problem. But in both stores, trying to access any website using Safari failed with a message about not being able to find the server. Now, in both stores the iPhone popped up its list of available WiFi networks and in both stores that list contained a single network called “nomad5.” In both cases the network was private, so I didn’t try to connect.

Am I seeing something nefarious where there is nothing? Is it just coincidence that in both of these Kroger stores I was unable to get on the EDGE network, despite the fact that I had a perfect signal? Is there some technical aspect that I don’t understand? I’d love an answer to this. There is a third Kroger that is about 5 minutes from my house, so I will try to get to it and run a test to see what happens there.