finncapt,
The action is being taken by UNITE (the country's second largest union) and not by BASSA or Amicus so I guess ultimately it will be UNITE who pays the bill if it all goes wrong. Presumably they have considered this in their calculations. That being said, I am unable to find any assurances in the blurb that is being sent out so would not like to swear to it!
As I read it, it is the court who has asked UNITE to provide the names of the crew who wish to proceed against BA but it does not say why. The original hearing was headlined as Malone v British Airways which is the name of one of BASSA's reps. Still no clearer really as to the risks. May have to wait to Feb to find out.