Just gonna add in that Blizzard can't legally do what it wants to in it's TOS, look at your computers memory and see if any offending program is running. They tried to, got sued, lost, and removed it. They can look at things going on in their memory space though but DB runs in a level outside their scope, why the program needs admin privileges to run. They can however use heuristics to profile your gaming behavior and look for possible slip ups by bad coding in profiles, plugins or DB.
Say you are repeatedly requesting to start a quest you don't have access to. How would you be sending those requests if you were legitimately playing the game as the GUI has it's own safe guards to prevent you from doing so. They don't publish what all the sensors would be as we would simply code around them and it would defeat the purpose for Blizzard. I just am giving you an example of one possibility.