? allowreselect.patch
Index: user_selectable_roles.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/user_selectable_roles/user_selectable_roles.module,v
retrieving revision 1.1.4.6
diff -u -p -r1.1.4.6 user_selectable_roles.module
--- user_selectable_roles.module	2 Sep 2009 23:34:45 -0000	1.1.4.6
+++ user_selectable_roles.module	22 Sep 2009 20:11:22 -0000
@@ -98,6 +98,12 @@ function user_selectable_roles_admin_for
     '#default_value' => variable_get('user_selectable_roles_editing', 0),
     '#options' => $options,
   );
+  $form['user_selectable_roles_allowreselect'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('User can select roles more than once'),
+    '#default_value' => variable_get('user_selectable_roles_allowreselect', 1),
+    '#description' => t('Select whether the user can select roles more than once; if checked in combination with the "Registration and user account forms" option above, the user will be able to switch between roles at will, which could be a security risk in some setups.'),
+  );
 
   return system_settings_form($form);
 }
@@ -156,6 +162,16 @@ function user_selectable_roles_user($op,
         }
         // fall through to insert case
       case 'insert':
+        if (!variable_get('user_selectable_roles_allowreselect', 1)) {
+          if (count($account->roles) != count(array_diff($account->roles, $user_selectable_roles))) {
+            return;
+          }
+        }
         // multiple choice checkboxes
         if (is_array($edit['user_selectable_roles'])) {
           $roles = array_filter($edit['user_selectable_roles']);
@@ -176,6 +192,16 @@ function user_selectable_roles_user($op,
         break;
       case 'form':
         if (!isset($account->uid) || variable_get('user_selectable_roles_editing', 0)) {
+          if (!variable_get('user_selectable_roles_allowreselect', 1)) {
+            if (count($account->roles) != count(array_diff($account->roles, $user_selectable_roles))) {
+              return;
+            }
+          }
           $user_roles = $account->roles;
           // remove anonymous and authenticated roles
           unset($user_roles[DRUPAL_ANONYMOUS_RID]);
@@ -271,4 +297,4 @@ function user_selectable_roles_validatio
       form_set_error('user_selectable_roles][user_selectable_roles', t('You must select one !label.', array('!label' => format_plural(variable_get('user_selectable_roles_mode', 0), $user_selectable_roles_label[1], $user_selectable_roles_label[0]))));
     }
   }
-}
\ No newline at end of file
+}