Actually a few weeks ago I cleared out my blacklist completely which had been growing since July. Before that day I'd only deleted the last few as I'd been told numerous times that RMT scum only last a few minutes.
Well, what a surprise I got when some of the names that had been near the top of the blacklist started to spam again. It seems like they're either reusing dormant accounts or they're recycling the list of names for characters.
As per the OP, it's getting terrible on Leviathan. I'm even getting the tell sound as I'm first logging in. They're spamming sometimes every 30 seconds then reducing to every few minutes.