That defeats the entire point of this arrangement, which allows them to investigate in situations where the legal requirements for obtaining a warrant are not met. (Which is the elephant in the room: the entire premise of this system is to bypass established legal thresholds).
> Although I am comfortable accepting that your agency demonstrates the integrity you indicate
I'm not sure that's a safe assumption. As you mention, system abuse by law enforcement is incredibly common at agencies across the country. If you talk to any person at one of those agencies, they will almost invariably tell you that their coworkers take their job seriously, that they never abuse their own power, and that they can't imagine their coworkers doing the same.