Caribbean Boy
This won't happen because any dismissal is illegal in the 12 weeks of industrial action so long as it is protected strike action. Protection is only possible where a proper secret ballot has been conducted in a 'lawfully organised' way. The employer cannot sue the union, and striking staff are protected from dismissal for a period of up to 12 weeks.
You are absolutely right but as has been posted on here before it is also illegal to murder, rape, pillage and commit genocide but people and groups still do it.
The old phrase "if you can't do the time (or in this case pay the fine) don't do the crime" comes to mind. For BA the benefits of the crime of sacking all the militants and those who wish an end to BA may be worth the fine imposed by a tribuneral in a couple of years.
There is also the possibility the strike, again, wasn't lawfully organised and therefore all those striking are doing so illegally.
Think carefully before you strike.
regards