Hi,
I think the latter. As far as I know, that's still forbidden here in Belgium to sell a phone locked to a certain operator. You're paying the full price in any case, so they have to let you choose your own operator.
To be sure, I can check it out tomorrow if it still matters.
sash
Just for reference of whoever finds this thread on Google:
My friend bought for me an iPhone 3GS in Belgium some time in Nov-Dec 2009 (don't remember the precise date), works perfectly in a different countries (in EU and out of EU) and completely different operators.