I've checked the search ingame for the "Brendens" and the others.
There is a huge number of "Brendens" without profile, i have found several hundreds of them!
Seems not all are from 2014, there are a lot of 8 or 9 years old ones. Technically it will be impossible to ban all these avatars, the ban list is limited.
This tells me one thing: Supporting such a huge number of bots costs a fortune. I can't believe this is just done for joy or hobby. Someone has a business and earns money.
I will try a simple trick: As it was said these avas rezz at a hight of around 3000 meters. I'll rezz a huge megaprim cube (256x256x256) centered at that hight and put a simple "teleport home on collision" script inside. Let's see if that helps.
Those searchbots definitely take ressources and collect unkown data. As long as i don't know exactly what these bots are doing i definitely don't want them on the sim i pay for.