Checking in online for other carriers is a hit-or-miss issue. I couldn't even do it for a UA flight with a BD flight number (nor could I change my seat, or even see what other seats might be available). I frequent the BMI board, as well, and it sounds to me like their computer system rivals united.com for errors, inefficiencies, and the like. If this problem was restricted to one airline, it would not surprise me that it was BMI (don't get me completely wrong -- they have a great intercontinental product and I like flying them, but their upper management is too similar to UA's).