2017 Tahoe - From observation, the "Take Steering" message appears whenever there is NO detectable motion in the steering wheel. Does not appear to be related to the placement of hands. Accelerometers in the wheel can detect even tiny motions, and will silence the message.
Just for fun, allow the Lane Keep Assist function to drive for a bit - notice that the steering control system soon diverges and lane excursions become too large to be safe. GM could adjust this, but people might freak out when they feel firm automatic corrections to the steering.