This has to be a FAQ
Unless you DISABLE EVDO (which you can do either on the phone, or just by calling *2 and saying "I want you to disable EVDO and 1X data access on line xxx-xxx-xxxx) then sure, any and every time you do something with networking and don't happen to be associated with a wifi network, the phone will connect and use EVDO or 1X at 2 cents per KB.
I'd call *2 and tell them to disable all data access on your line. After that, if you happen to do something and the phone tries to connect, it should give you an error message instead of a billing surprise.