Special forces alarm posts would be pretty nifty if you wanted to get all of them out of the way at once, except that, IIRC, they are broken right now (triggering them does nothing)...
They were reactivated when threatfleet behavior was added: trigger the sf-alarm, and all sf become threatfleet.
For dealing with SF, if it's really truly killing you, then something like LordSloth described should work:
- capture a planet next to a CSG planet
-
without taking the CSG planet build a sufficiently intense beachhead (turrets, forts, forcefields, etc) on the CSG planet
- once you've broken the SF fleet's initial attacks, you just have to deal with the ongoing spawns, but they should all happily march into your beachhead and die (unless you start hitting them somewhere more important, but at least they won't have a full fleet)
Of course, if the AI's SF forces you to do something like that it's already accomplished a large part of its purpose (making your life difficult), but they shouldn't ever be a total wall if you know how to handle them.
The strategic reserve on the homeworld, on the other hand...