Echoing an email here:
"- We are unable query for the bearerName of default connection on phone - QNetworkConfigurationManager::defaultConfiguration() - the QNetworkConfiguration::bearerName() returns empty string

• We have noticed a strange behaviour where if using the default connection and it happens to be a wifi not in range the application either takes a very long time to connect or it never does if we implement a time out. On the other hand if we just try to connect without trying getting the default connection the application seems to quickly switch to the second working connection.
• This seems to be a feature of the N8 but if the user has not actively connected to wifi before the app, the app will always connect using the default handset connection at the top of the IAP priority list. If the app uses the default connection for the main app, when playing a video, it will automatically switch to the connection as defined in the video streaming settings. On the other hand if the user connects to wifi before he starts the app, the application seems to be using the wifi connection throughout.
  "

Most likely also same behaivour in mobility bearermanagement and other Symbian platforms than S^3