From the EU paper in the link below
Can a strike be considered as an extraordinary circumstance?
Yes, under certain conditions. Recital 14 of the Regulation states that strikes can constitute
extraordinary circumstances. A case-by-case assessment will remain crucial taking into
account all relevant jurisprudence and legislation in force in the country of the incident.
They can wriggle out of compensation with this one.
http://ec.europa.eu/transport/passen...g_2004_261.pdf
See page 8