I've been at the Christmas market this Sunday, sipping on mulled wine. I gotta say, it seems quite calm in Brussels, but mainly because most of the people are out of the city/hiding at home. With soldiers at every corner, it does look calm, but also quite depressing. Nevertheless, I managed to catch the Light show on Grand Place (they've also built there a hut with real sheep, and some mannequins representing Jesus's birth) and truly felt the athmosphere of the big Christian holiday. I would say it's not worth it to go, if you're going to worry about your family all the time, though.