[Dubdub]

But did you also read this "Typically a BB, when connected to WiFi, will send data via that route rather than through your carrier's cell plan".

If you turn data services off, you cannot use WiFi for data - i.e. no email, no BBM, etc. since those use data.

You are correct in that if you turns network services off, you will lose phone capability and all services related to that, but you should be able to access data using WiFI.