So by that logic they cant do whatever they want without letting imu know tho.
Imu is not actively involved in the day to day running of the World Government, that's what the Gorosei are for.
As best as we can tell, she rarely takes action personally. The last time she acted may well have been erasing God's Valley.
That said, the Gorosei worship Imu and so would never defy her will.