Hard to decide. Should the white hatters get enough information to deal with a problem at the risk of informing the black hatters something they did not know?

Or do you assume the black hatters already have access to all the information they want to know, and it is only the white hatters who are left in the dark by hiding information ?

They are probably already aware of this if they do this sort of black hat SEO type stuff.

Yeah, this particular technique is as old as the hills.

CVE-2007-1287 was abused for this specific purpose over a decade ago, and remnants of that still occasionally show up in google indexes.