Last Friday I reported that I was stuck at a Starbucks that did not have a reliable WiFi connection, so I decided to give the iPhone tethering a try. That trial ended up lasting 4 hours of work on my Mac. When I decided to use it, I was not 100% certain how Smartone-Vodafone was going to bill me. I have one of their IOM (Internet on Mobile) plan that has since been discontinued, but very similar to the current "IOM Value Pack" except without a contract.
This plan comes with a HKD15.00/15MB rate for any HSDPA traffic outside of their "Internet Browsing" traffic. So I concluded that Smartone-Vodafone cannot tell the difference between regular local data traffic and tethered traffic from my Mac. Therefore and tethered traffic will be charged based on the HKD15.00/15MB rate (with a price cap of HKD298.00).
I received my bill yesterday and I was correct. The only extra data charges I have was lump into the other HSDPA traffic that Smartone-Vodafone did not consider to be "Internet Browsing". It came out to about 105MB of usage for the 4 hours of tethering.
Today I also received confirmation of how Smartone-Vodafone's billing system is distinguishing regular HSDPA local data traffic and what they considered "Internet Browsing". For the iPhone:
Any traffic through the Mobile Safari browser on the iPhone and any traffic from the use of the YouTube native application are all considered "Internet Browsing" according to the Smartone-Vodafone billing system.
All other HSDPA data traffic from any other applications on the iPhone will be considered extra data, and will be charged based on the HKD15.00/15MB rate with a price cap of HKD298.00.
Also, the HKD298.00 is a price cap only, that means HKD298.00 is the maximum amount Smartone-Vodafone will charge for extra data usage, but if you reach that amount the data usage is still usable past the 298MB.
I hope this helps clarify some of the questions people have with using the iPhone in Hong Kong on the Smartone-Vodafone network.