The ADT company hired and trusted convicted serial killer Dennis Rader to install alarms. He'd then defeat the alarms and go in to the houses to bind, torture, and kill his victims.
As far as most people were concerned, Dennis Rader was a normal member of community. I used to live in Wichita where he operated. One of my coworkers had had dinner with them because they went to the same church as him.
See: https://en.wikipedia.org/wiki/Dennis_Rader#Early_life_and_ca...
Your analogy is good. Google and Chrome Adblocker is just like ADT and the "BTK Killer".