JOINT physical custody isn't about "sharing."  It's about splitting the spoils (in this case, rendering children possessions) down the middle to "share" in the sense of halving.

It's about operating separate automonous households that do NOT have to confer, because EACH can do whatever the heck it wants to, consistent or not, approved by the other parent or not.  

Inspired by the ad on page 35 of the Spring 1999 Family Advocate, Vol 21, No.4, American Bar Association, and dedicated to the pursuit of financial advantage and blatant commercialism everywhere.