They do seem to make arbitrary changes for their own purposes.
I get the impression it is more about consumption during the journey and unruly passengers rather than importation limits.
Kim, you are very bad!
They are not restricting sales on board though but.
plus the empty re-fillable 1l bottle to mix them all back into again
The head of the committee which dreamed this up must be a MCC member and have therefore copied the alcohol restrictions into Lords Cricket ground