Whilst being part of an alliance can be a good thing for an airline by opening up new markets etc., it can also bring with it a million and one problems, mostly due to how each airline computer system talks to the other.
The article states that even a new employee should be able to tell if a ticket has or has not been issued, unfortunately this is not the case. Quite often the agent only has access to what is called "an informational PNR (Passenger name record)" and all this shows is the name(s) and routing (flight no./date/class etc) and this is the case with United and bmi systems so if the issueing carrier has failed to issue the ticket (as in this case) or has not passed control to the operating carrier the check-in process basically grinds to a halt
Moto of the day......always have your actual e-ticket number handy @:-)