Agreed.
OTOH, I do like the idea that when they have a series, they keep changing constantly; why would they suddenly stop dead just because they don't have one?
They don't know they don't have a series, and Canada hasn't (presumably) stopped being attacked.
So: a writer should combine those ideas. When AF appear, have them reference adventures we've never seen - to whet fans' appetites.
Make people wonder what they're missing until they demand a series to find out!
~ Le Messor
"A friend is one to whom you may pour out all the contents of your heart, chaff and grain together, knowing that the gentlest of hands will take and sift it, keep what is worth keeping and with the breath of kindness blow the rest away."
~ Arabian Proverb