great idea, and a real time saver. However, at DME, when you try to go through to the security scanners, after passport control, they get really upset because you don't have one of those stupid stickers they put on the back of your passport which means you have been "security checked" (ie asked if you packed your own bags etc)

A couple of times the woman was going to send me back to checkin, but I played dumb enough and refused to move and she eventually waived me through.

So, great idea, but BA do need to think a little more on what happens to a pax from checkin to boarding to make sure they have all the bases covered. (BTW, if you are at DME, just stop by the BA checkin desks and the person there will put a sticker on the back, saves time and hassle for later)