Thanks.. I wasn't so much concerned whether the religion would accept my conversion, but whether the GOVERNMENT would..
In other words, if I'm a Muslim, and they're stopping Muslims at the border, can I convert to Christianity on the plane, and then convert again to Islam in my car on the way home?
Since there isn't a way to know definitively whether you are a Muslim, a Christian, or a Jew just by looking at you, if you say that you're a Christian when a minute before that you were a Muslim, how will border agents know you have pulled an insta-conversion?