The organizations that think they have an "honorable" purpose are the worst offenders of all.
Info Trackers and Mark Scanners as I usually call them.
The Mark scanners especially, out hunting for trademark abuse and stolen copyrighted images and content.
They think that because they serve a "righteous" purpose they have the right to rip off whole web-sites and every image on a site to check it all. Over and Over.
Mark Monitor is one of the worst of all, although there are quite a few of them. Cyveilance and Name Intelligence (also owns Domain Tools [dot] com) just to mention a couple.
Plus, Mark monitor has now added at least one shell company (recently named "Brand Certified" with different IP ranges) to hide some of their activities behind.
I have added all the IP ranges I know for them to my DNSBL blocks as policy blocks. I do not want to see them, and they are met with nothing but 403's.
I have absolutely no stolen content, and they are welcome to "investigate" by hand using normal human visitors.
But just as I would not let all these "private detectives" into my house to riffle through all my closets and drawers to check if I might own counterfeit Nike's, fancy hand-bags, or have a drawer full of stolen gold-watches, without the police and a court-order at their side, I will not have them steal my server and network bandwidth either, "just in case I might be a thief". They are really abusive, running much faster that any other normal bots.
Having a "righteous" cause does not make network and server bandwidth theft legal.
By Texas law, I could haul them off to court for hacking and illegal access. So also in many other states that have similar laws against "unauthorized" access to a network or server.