What has not been made clear here as yet is that ST has been removed from employees in the past for taking Industrial Action.
During the Gate Gourmet dispute a number of TGWU (Unite) shop stewards were disciplined by BA for unlawful action.
Some where dismissed and others had their ST removed for life as a punishment.
I do not remember any court cases, human rights claims etc being made for them by the union.
If this cabin crew ST dispute gets to court I would imagine the BA brief will immediately bring this information forward.