Even if he's a young enthusiast, he's allowed to ask this question.
So here is the answer:
A330 does flex take-off like any other airliner. It all depends on how heavy she is and how the atmospheric conditions are. If you are close to the max take-off mass, and it's hot, you can safely assume that there isn't much to flex. Otherwise, flex is very common and you flex more often than not.
Just by watching the aircraft lifting off and by counting the occupied seats, you cannot assume if it's flex or max. The trick behind flex is that you flex that much that you just make it off the runway (or stop her in case of failures before V1). So in the ideal case the aircraft always "seems pretty heavy", no matter if she is heavy or not. If you would take off with a flex value other than optimal, you would give away precious fuel and engine life time. It's all calculated to be safe, economic and efficient.
hth,
Dani