Similar thing has happend numerous times at LHR too. Pax travelling X airline, but main rival airline's aircraft parked on gate with jet bridge attatched - pax boarding downstairs onto busses. Staff member in gate and staff member outside waiting for pax to board busses. You can guess where the pax ended up can't you - it wasn't on the busses !!. The a/c had NO crew or NO lights on - wouldn't that set alarm bells ringing as a pax ??? - Not in this case, not one of them !!! They were all sat down in their seats with h/luggage stowed !!!
All because there are NO doors/straps to block off the jetty to direct people down the stairs !!. This is on just about every single gate I've ever used at LHR !!.
The BAA really need to consult with the staff that actually use the facilities, rather than the airlines management who don't !!!.
Calling the faults line to report things is a waste of time too. It can take months if not years to get even the most simple things fixed !!.