S ranks give a zone shout (I think? haven't seen an S in ages...). B ranks, if you've got the hunt bill for them, have a proximity notice. Is there no in-game method of knowing if an A rank is up or if you're flying over/near them?

Just happened to be cruising around for the old ARR hunts, just for funsies, see what I can solo, see what mechanics they have, had trouble finding a lot of them. Not knowing whether they're on cooldown or I just didn't look well enough.