Index: bin/df/df.c
===================================================================
--- bin/df/df.c
+++ bin/df/df.c
@@ -261,6 +261,7 @@
 					free(mntpath);
 					continue;
 				}
+				warnx("df on unmounted devices is deprecated");
 				if (iov != NULL)
 					free_iovec(&iov, &iovlen);
 				build_iovec_argf(&iov, &iovlen, "fstype", "%s",