I think with these FATEs they could even get away with making a server announcement (kind of like how you see text when your retainer sells something). It could say something like "Something is amiss in the Shrouds/Dravanian Forelands/Azys Lla" it would get people's attention and get them there and hunting.

I find Odin gets called out frequently in the Novice Network. The other two are a lot less common, as novices have lose their access to the network at this point and they would be the ones most likely to come across these FATEs.