The package operations possible in any non-global zone are:
If a package is not currently installed in the non-global zone, the package can be installed only if SUNW_PKG_ALLZONES=false.
The package can be installed in the current (non-global) zone, if SUNW_PKG_THISZONE=true.
If a package is currently installed in the non-global zone:
The package can be installed over the existing instance of the package only if SUNW_PKG_ALLZONES=false.
The package can be removed from the non-global zone only if SUNW_PKG_ALLZONES=false.