Helol, from Lux, if you have some time, don't bother standing at the airport for two hours if you can catch a fast EC/IC to Bruxelles Midi and the Eurostar to St Pancras. So much less hassle. :-)
And Seat62K, actually the security is a barcode, just not the traditional one used for UPC/EAN. The traditional barcodes hold very limited information. 2D barcodes, which are square and look like a bunch of gobbledigook and which you often see on tickets, hold a lot more information, which can then be read and reconciled with you at the security checkpoint.
However, 2D codes require much more accurate scanning. Tesco (or any other grocer/shop) use laser scanners that use multiple beams in multiple configurations (dimensions and angles) to avoid the problem of having to scan the traditional barcode in one specific direction, however, they'll need better and different scanners to read a 2D barcode. Japan is VERY good at those barcodes, they use them everywhere... the old barcodes used for ISBN/UPC/EAN are very much in the minority. I have to agree with you though... don't fold your ticket where the barcode (whether UPC or 2D) is. And print it on a laser printer, ink smears/smudges, and is a problem then.
:-)
S.