How to Disable data services on iPhone 4?

How to disable data on iOS 4 on iPhone 4? Are these steps sufficient to prevent data charges when using a Pre-Paid SIM in an iPhone 4 ?

Settings > General -> Network > Cellular Data > OFF

Settings > General > Network > Data Roaming > OFF

Settings > Mail, Contacts, Calendars > Fetch New Data > Push (Off) & Fetch (Manually)

Settings > Mail, Contacts, Calendars > Accounts (set ALL existing accounts to OFF).

Settings > General > Location Services > OFF

Settings > Notifications > OFF

I have been told that every time the following are done, it resets iPhone to default factory settings:

• Insertion of a new or different SIM

• Restoration of the iPhone from iTunes

• Updating of the firmware version