I think I've found out why the beer is so cheap there...it seems they've got someone to shake some of the bottles resulting in a mess of beer when you open the bottle (happened on a Gulden Draak and Chimay Red for me...some Kwak I had was fine though).
Actually, is there any way of reducing the risk of massive spillage of a shaken bottle? I doubt simply opening the bottle slowly and carefully would have made much difference with those two