it's been happening for several years at Ba...it is down to c/crew shortages and whilst it does protect the slots, it also gets the c/c in their correct position, as Ba c/c operate numerous 'back-to-back' rotations.ie 4 t/a sectors. If the crews 2nd sector is canx due lack of crew, they then are delayed a day making a 4 day slip and therefore knocking them off the 2nd part of the BTB, hence compounding the crew shortage, so they operate the a/c with nil pax and cargo only to get the c/c in the correct position to operate the next sector.
I can't believe what I'm reading. Who's in charge of this debacle? The cost of this is completely avoidable, with proper planning of course.