If I got one, which I wouldnt...but if I did, I would likely use it for note taking or the similar. In those cases, I would probably have a briefcase or bookbag with me, so I would just carry it around in there.
I had the BT Apple keyboard and after traveling with it once with my iPad, I decided to not take it with me for future trips. I found it much easier to just shoot out an email, etc with the virtual keyboard and I got pretty good at it too.