I've tried it while roaming, and it works fine. And when out of the country I turned the cell network off and used wi-fi without a problem, since I don't have an international plan.
Choosing the "turn data off while roaming" and using wi-fi should work for you. If you get a charge for it (unlikely, I haven't had this problem), then I'd say you'd have a good basis for arguing with the provider about that one.
Silly question
Wifi allows data to be pushed to the bb. So if you swithch off data then wifi data is included. Yes wifi is free and data via mobile network costs a lot and most people with personal bb's probably switch off their data when they go abroad but still you asked a dumb question matie
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