Just a comment...I am not an airline Capt.
If there was even a chance of an escort of CF-18s showing up I would certainly advise the cabin crew of the possibility and if an escort was actualy going to formate make a cabin announcement, using my best "This is your Capt. and the everything is under control" voice in order that folks would know what to expect and not panic if they ever stopped filming with their iphones long enough to look out a window. I would use the term "escort" instead of "Intercept".