The find_package command, on Windows, has always searched build trees
recently visited by cmake-gui (or CMakeSetup at one time).  This was
done when the command was created with the intention of simplifying
workflows involving building multiple dependent projects.  However,
this behavior depends on recent developer interaction and therefore
can create different find results based on transient system states.
It can lead to surprising results and user confusion.

Since this behavior was first added CMake has gained many more search
options, better error messages when a package is not found, and a
package registry.  The latter in particular allows projects to make
their build trees available for dependent projects to find without
user intervention.  Therefore the originally intended workflow can
be achieved in other, more stable ways.

After the above evoluion of find_package we have now decided that
the magic search-where-cmake-gui-was behavior does more harm than
good.  Drop it.  We do not need a policy for this behavior change
because it only affects interactive use.