diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1934,6 +1934,7 @@
     'PhabricatorBoardLayoutEngine' => 'applications/project/engine/PhabricatorBoardLayoutEngine.php',
     'PhabricatorBoardRenderingEngine' => 'applications/project/engine/PhabricatorBoardRenderingEngine.php',
     'PhabricatorBoardResponseEngine' => 'applications/project/engine/PhabricatorBoardResponseEngine.php',
+    'PhabricatorBoolEditField' => 'applications/transactions/editfield/PhabricatorBoolEditField.php',
     'PhabricatorBot' => 'infrastructure/daemon/bot/PhabricatorBot.php',
     'PhabricatorBotChannel' => 'infrastructure/daemon/bot/target/PhabricatorBotChannel.php',
     'PhabricatorBotDebugLogHandler' => 'infrastructure/daemon/bot/handler/PhabricatorBotDebugLogHandler.php',
@@ -4426,7 +4427,7 @@
     'ConduitAPIRequest' => 'Phobject',
     'ConduitAPIResponse' => 'Phobject',
     'ConduitApplicationNotInstalledException' => 'ConduitMethodNotFoundException',
-    'ConduitBoolParameterType' => 'ConduitListParameterType',
+    'ConduitBoolParameterType' => 'ConduitParameterType',
     'ConduitCall' => 'Phobject',
     'ConduitCallTestCase' => 'PhabricatorTestCase',
     'ConduitColumnsParameterType' => 'ConduitParameterType',
@@ -6363,6 +6364,7 @@
     'PhabricatorBoardLayoutEngine' => 'Phobject',
     'PhabricatorBoardRenderingEngine' => 'Phobject',
     'PhabricatorBoardResponseEngine' => 'Phobject',
+    'PhabricatorBoolEditField' => 'PhabricatorEditField',
     'PhabricatorBot' => 'PhabricatorDaemon',
     'PhabricatorBotChannel' => 'PhabricatorBotTarget',
     'PhabricatorBotDebugLogHandler' => 'PhabricatorBotHandler',
diff --git a/src/applications/conduit/parametertype/ConduitBoolParameterType.php b/src/applications/conduit/parametertype/ConduitBoolParameterType.php
--- a/src/applications/conduit/parametertype/ConduitBoolParameterType.php
+++ b/src/applications/conduit/parametertype/ConduitBoolParameterType.php
@@ -1,7 +1,7 @@
 <?php
 
 final class ConduitBoolParameterType
-  extends ConduitListParameterType {
+  extends ConduitParameterType {
 
   protected function getParameterValue(array $request, $key) {
     $value = parent::getParameterValue($request, $key);
diff --git a/src/applications/diffusion/editor/DiffusionRepositoryEditEngine.php b/src/applications/diffusion/editor/DiffusionRepositoryEditEngine.php
--- a/src/applications/diffusion/editor/DiffusionRepositoryEditEngine.php
+++ b/src/applications/diffusion/editor/DiffusionRepositoryEditEngine.php
@@ -132,6 +132,16 @@
         ->setConduitDescription(pht('Change the default text encoding.'))
         ->setConduitTypeDescription(pht('New text encoding.'))
         ->setValue($object->getDetail('encoding')),
+      id(new PhabricatorBoolEditField())
+        ->setKey('allowDangerousChanges')
+        ->setLabel(pht('Allow Dangerous Changes'))
+        ->setIsCopyable(true)
+        ->setIsConduitOnly(true)
+        ->setTransactionType(PhabricatorRepositoryTransaction::TYPE_DANGEROUS)
+        ->setDescription(pht('Permit dangerous changes to be made.'))
+        ->setConduitDescription(pht('Allow or prevent dangerous changes.'))
+        ->setConduitTypeDescription(pht('New protection setting.'))
+        ->setValue($object->shouldAllowDangerousChanges()),
       id(new PhabricatorSelectEditField())
         ->setKey('status')
         ->setLabel(pht('Status'))
diff --git a/src/applications/diffusion/management/DiffusionRepositoryBasicsManagementPanel.php b/src/applications/diffusion/management/DiffusionRepositoryBasicsManagementPanel.php
--- a/src/applications/diffusion/management/DiffusionRepositoryBasicsManagementPanel.php
+++ b/src/applications/diffusion/management/DiffusionRepositoryBasicsManagementPanel.php
@@ -26,6 +26,7 @@
     $activate_uri = $repository->getPathURI('edit/activate/');
     $delete_uri = $repository->getPathURI('edit/delete/');
     $encoding_uri = $repository->getPathURI('edit/encoding/');
+    $dangerous_uri = $repository->getPathURI('edit/dangerous/');
 
     if ($repository->isTracked()) {
       $activate_icon = 'fa-pause';
@@ -35,6 +36,17 @@
       $activate_label = pht('Activate Repository');
     }
 
+    $should_dangerous = $repository->shouldAllowDangerousChanges();
+    if ($should_dangerous) {
+      $dangerous_icon = 'fa-shield';
+      $dangerous_name = pht('Prevent Dangerous Changes');
+      $can_dangerous = $can_edit;
+    } else {
+      $dangerous_icon = 'fa-bullseye';
+      $dangerous_name = pht('Allow Dangerous Changes');
+      $can_dangerous = ($can_edit && $repository->canAllowDangerousChanges());
+    }
+
     return array(
       id(new PhabricatorActionView())
         ->setIcon('fa-pencil')
@@ -49,6 +61,12 @@
         ->setDisabled(!$can_edit)
         ->setWorkflow(!$can_edit),
       id(new PhabricatorActionView())
+        ->setIcon($dangerous_icon)
+        ->setName($dangerous_name)
+        ->setHref($dangerous_uri)
+        ->setDisabled(!$can_dangerous)
+        ->setWorkflow(true),
+      id(new PhabricatorActionView())
         ->setHref($activate_uri)
         ->setIcon($activate_icon)
         ->setName($activate_label)
@@ -110,6 +128,20 @@
     }
     $view->addProperty(pht('Encoding'), $encoding);
 
+    $can_dangerous = $repository->canAllowDangerousChanges();
+    if (!$can_dangerous) {
+      $dangerous = phutil_tag('em', array(), pht('Not Preventable'));
+    } else {
+      $should_dangerous = $repository->shouldAllowDangerousChanges();
+      if ($should_dangerous) {
+        $dangerous = pht('Allowed');
+      } else {
+        $dangerous = pht('Not Allowed');
+      }
+    }
+
+    $view->addProperty(pht('Dangerous Changes'), $dangerous);
+
     return $view;
   }
 
diff --git a/src/applications/transactions/editfield/PhabricatorBoolEditField.php b/src/applications/transactions/editfield/PhabricatorBoolEditField.php
new file mode 100644
--- /dev/null
+++ b/src/applications/transactions/editfield/PhabricatorBoolEditField.php
@@ -0,0 +1,23 @@
+<?php
+
+final class PhabricatorBoolEditField
+  extends PhabricatorEditField {
+
+  protected function newControl() {
+    return id(new AphrontFormSelectControl())
+      ->setOptions(
+        array(
+          '0' => pht('False'),
+          '1' => pht('True'),
+        ));
+  }
+
+  protected function newHTTPParameterType() {
+    return new AphrontBoolHTTPParameterType();
+  }
+
+  protected function newConduitParameterType() {
+    return new ConduitBoolParameterType();
+  }
+
+}