Do you guys find that transporting them in the plastic cases with foam inside keeps the scope from getting knocked off zero?
Yes definately! I once had a Leupold lose zero on me that was in a padded bag riding in the back of the truck just coming home from the range. But I guess that was enough to throw it off.
So now once I have a gun sighted in for hunting season, no matter where it goes, it goes in a hard plastic case. My MLs are all sidelocks and do not use scopes. For those I will use either the padded bag or hard case with the lock facing up.