getting emails on Wifi while roaming

I am on Rogers in Canada with a BB bold 9000. I am currently in France and did not want to incur roaming charges for data. I went to options>mobile network> and set data services to "on" and while roaming to "off". Using this configuration, as expected, my emails were not coming in and I could not browse. Then I logged into the hotel's Wifi network, and again as expected, I could now browse BUT, in addition, all my emails (which are routed through the BB server) also came in on the native BB email app. I was surprised by this, and worried that despite having the setting as "off while roaming", I was still incurring data roaming charges.

I called Rogers on Skype and found out that I was not incurring roaming charges. Obviously I am pleased about this, but I don't understand how it is happening...emails from my email server go to BB server then routed to my BB via internet and picked up through wifi? Anyone have a good explanation? Does this work for all carriers? :confused:

Yes. Wifi can be used to support Unlicensed Mobile Access (UMA) or BIS access through Wifi.

The difference is the availability of Voice and SMS text when UMA is active.