If you turn cellular data off in the iOS settings app for RSSRadio (Settings, RSSRadio, "Use Cellular Data" or Settings, Cellular, RSSRadio), you may see repeated prompts similar to the following:
These prompts are part of iOS, and not part of RSSRadio.
As of version 3.4.4 RSSRadio contains switches to restrict both downloads and podcast refreshing on cellular data:
Setting these switches will achieve the same as the iOS setting, but without the annoying prompts. In addition you can also add new podcasts and browse the directory when you are out and about.