The times I've arrived internationally and been through Zaventem / BRU I've merely walked out, nothing to declare, and have had no interaction with Belgium customs personnel.

My only troubles have been building my resistance when I'm departing and walking by Belgian chocolates on offer.

Thank you for asking.

P.S. I may be one of the very few who have 1) experienced a terror bombing (the secondary bomb, designed to take out responders, was identified and disabled before it detonated, or I'd probably not be writing), and 2) been on an aircraft where smart security identified a bag / passenger mismatch and a probable explosive device was identified when we had to retrieve our baggage and re-check it prior to the (Pan Am) flight being released.

Though I resent bullying and arrogance when it occasionally rears its head - either way, passenger on agent or vice versa - (Dayton, Ohio a few years ago for me), I do understand why certain security procedures exist.