The French whether justified or not at least strike in the correct manner!
CDG a couple of years ago; checked in for an early duty, no mention of any problems, no pertinent NOTAMS, everything hunky-dory; after getting to the aircraft, and mid-way through boarding passengers, we call for our clearance, to be told "you have a slot in two and a half hours", with no further information. Eventually it transpired that the tower had just gone on strike. Not exactly what I'd call the 'correct manner'!