cannot see how the canopy could open wide enough to cause the a/c to become unmanageable.  I have though about putting a little hand grab at the rear of the canopy to allow the pilot or passenger to close it but have not yet done so.

The Bonanza/ Baron crowd loses one to two aircraft a year due to the passenger door opening on takeoff. It is startling and is noisy but results in no aerodynamic problem for the aircraft. Unfortunately, some pilots do not know that, freak out and lose control of the airplane trying to close the door. Remember, fly the airplane.

 

Jeff