Closing the blinds
This beggars belief.
Failing to comply with a legitimate management instruction is readily accepted by Employment Tribunals as grounds for Summary Dismissal (as long as a fair process is followed).
As has been pointed out, the "cabin crew" already pull down blinds in-flight, so it is reasonable for management to take the view that it is a legitimate part of the "cabin crew's" duty not requiring additional assessment, training or whatever. Management have a sound business reason for the blinds to be pulled down at the end of a flight, and included in the "cabin crew's" tasks (they are highly trained professionals after all).
A refusal to comply, whether polite or otherwise, is inviting dismissal. Would some poor unfortunate, following their union's advice, have grounds to sue BASSA/Unite after their dismissal was found to be fair by a Tribunal ?