We used them at AoA last year without any issue. We didn't try the pull out couch bed though, so that may be what you are referring to? No problem with the Murphy bed or master bedroom bed though.
How old is the child? We never used bed rails at home, so we never traveled w/ them either. Seems like a pain in the neck. You could put pillows on either side of the bed under the sheets, it will make a barrier.