Iphone 4 radio app works under 3G | Phone/Device Issues and Features | Consumer forum

Today, I walked out the door with my Iphone 4 and a radio app (ooTunes) tuned to a local radio station using my wifi connection in the house. Walking away from the house, I expected the radio app to stop as I never had it work using the 3G connection. But it didn't stop. I'm sure it used to not work using Speakout 3G . Anyone else use a Iphone radio app (I think Tunein is one of the more popular ones) and have it work? Was I just confused about it not working under 3G before?