diff --git a/src/land/engine/ArcanistGitLandEngine.php b/src/land/engine/ArcanistGitLandEngine.php
--- a/src/land/engine/ArcanistGitLandEngine.php
+++ b/src/land/engine/ArcanistGitLandEngine.php
@@ -885,6 +885,11 @@
             $onto_ref));
       }
     }
+
+    // TODO: Check that these refs really exist in the remote? Checking the
+    // remote is expensive and users probably rarely specify "--onto" manually,
+    // but if "arc land" creates branches without prompting when you make typos
+    // that also seems questionable.
   }
 
   protected function selectOntoRefs(array $symbols) {
@@ -1491,7 +1496,7 @@
 
     foreach ($this->getOntoRefs() as $onto_ref) {
       $refspecs[] = sprintf(
-        '%s:%s',
+        '%s:refs/heads/%s',
         $this->getDisplayHash($into_commit),
         $onto_ref);
     }
diff --git a/src/land/engine/ArcanistLandEngine.php b/src/land/engine/ArcanistLandEngine.php
--- a/src/land/engine/ArcanistLandEngine.php
+++ b/src/land/engine/ArcanistLandEngine.php
@@ -1361,7 +1361,7 @@
     }
 
     $into = $this->getIntoArgument();
-    if ($into && ($into_empty !== null)) {
+    if ($into && $into_empty) {
       throw new PhutilArgumentUsageException(
         pht(
           'Arguments "--into" and "--into-empty" are mutually exclusive.'));