I cannot get my head round this one!
You can buy a seat on line, get your seat number so you know what sort of aeroplane it will be so..... why can't the crew be rostered and FLY the roster they are given.
Standardisation of aircraft means that all your pilots can fly all your aircraft. I accept there must be roster changes due to training committments.
I felt for a long time that the sub-culture at the management level that was endemic in the bmi crewing department was the root of their problems.
Don't shoot the messengers!
MP