Our experience and in chats with my TA and crew.
Most lines have the Autotip method and if you have allowed that in full then the crew who have access to that information are not required to put your extra cash into the pool.
If you have reduced or removed than they are required to place in the pool.
I just found out thru a recent post ,MSC Poesia - Cruisemates Reader's Cruise Reviews
and verified with the author that MSC collects your autotip but it does not go to the crew as they say it is insde their wages. Most of the passengers on that voyage removed theri autotip.
Who said life was easy..