I beg to differ on that they can, and are.
Even though they never were intended to be used in such a manner. However, yes the sim was intended to be used in the way you stated but a few of us have worked a way around that for varying reasons
Posted from my CrackBerry at wapforums.crackberry.com
You mean just unlocking the phone and using a different sim or a way to get the Vodafone NL sim to roam for free on america carriers?