Same version as this one, how odd.
And no, the roaming thing in status is most likely referring to its current state only. The moment you leave your network area, it may possibly start roaming.
Best thing is to simply disable 3G all together before you leave. There has to be something under 'Mobile network' that allows you to do that, like an option called 'Data enabled'.
EDIT: Actually, isn't there a checkbox under 'Wireless & networks' called 'Mobile network'?