I can't imagine this. I would never be able to sleep for fear of smothering them! Besides, who wants poopies in their beds!
But I have had a couple friends who have very large birds, and at times let them sleep in the bed with them. I still don't see it, but to each his own I guess!
One of these friends was my boyfriend, and he had this huge red parrot that he let have the run of the house most of the time. I was terrified of this huge bird and didn't know anything about any birds at the time. I would wake up and he (the bird)would be like, a foot from my face, staring at me!! Jeez, it scared the daylights outa me, because I DID know how their beaks had all this pressure that could take off your finger in a second!!