Advise authors to use the _guarded versions of the APIs, instead.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20230427211013.2994127-4-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>