The fey (elves, eladrin, gnomes, etc) tend to stay attached to the Feywild, only occasionally coming to visit this “flawed” world, normally to take their progeny (half-elves, for example) back to the Feywild.
It is thought that the fey became involved in The Ancient Alliance during the original wraith war (perhaps their natural affinity toward magic & stealth gave an extra string to the dwarven bow), however, there has been no approach to The New Alliance. This seems to have caused some anger amongst those who have already suffered considerable loss during this war.
One of the high end Wraith-Hunter Groups is (apparently) operating currently in the Feywild, although their mission is not widely known. It may be that the Alliance want to remind the Fey that the Wraith can just as easily infiltrate their plane of existance as any other. The fact that the Feywild is thought to be naturally bound to the Chaos Plane potentially makes the situation even more dangerous.