nuclear weapon
You are correct. Fixed links are definitely preferable. But just to give you a glimpse into the 'BA way'. I have in the past, worked a four sector day, on four different aircraft (including three different variants) with four different groups of cabin crew.
It is also perfectly possible, on a five day gypsy tour of Europe, to operate with TEN different lots of cabin crew!
That's what BA affectionately term 'One Team'!