What you morons calling crews 'scabs' need to realise is that under UK law refusing to crew a flight on the grounds that it's to cover industrial action is illegal and will lead to your instant dismissal.
+1.
In some European countries you can hold a strike/refuse to work across borders/work to rule at the drop of a hat with reasonable impunity, safe in the knowledge that when your Union say it's OK you can rock back up to work and suffer negligable consequences.
Do that in some other countries and unless you're union has been very clever you're fired for indulging in illegal industrial action, and there's no protection in law. It's yet another example of how European pilots associations are struggling to cope with hard driving pan-European businesses.