Augment the comment for blacklisted extensions to make it clear they will get...

chrome/app/policy/policy_templates.json

 {
 # policy_templates.json - Metafile for policy templates
 #
 # The content of this file is evaluated as a Python expression.
 #
 # This file is used as input to generate the following policy templates:
 # ADM, ADMX+ADML, MCX/plist and html documentation.
 #
 # Policy templates are user interface definitions or documents about the
 # policies that can be used to configure Chrome. Each policy is a name-value
@@ skipping 612 matching lines @@
       'caption': '''Extensions''',
       'desc': '''Configures extension-related policies. The user is not allowed to install blacklisted extensions unless they are whitelisted. You can also force <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> to automatically install extensions by specifying them in <ph name="EXTENSIONINSTALLFORCELIST_POLICY_NAME">ExtensionInstallForcelist</ph>. The blacklist takes precedence over the list of forced extensions.''',
       'policies': [
         {
           'name': 'ExtensionInstallBlacklist',
           'type': 'list',
           'supported_on': ['chrome.*:8-'],
           'features': {'dynamic_refresh': 1},
           'example_value': ['extension_id1', 'extension_id2'],
           'caption': '''Configure extension installation blacklist''',
-          'desc': '''Allows you to specify which extensions the users can NOT install.
+          'desc': '''Allows you to specify which extensions the users can NOT install. Extensions already installed will be removed if blacklisted.
 
           A blacklist value of * means all extensions are blacklisted unless they are explicitly listed in the whitelist.''',
           'label': '''Extension IDs the user should be prevented from installing (or * for all)''',
         },
         {
           'name': 'ExtensionInstallWhitelist',
           'type': 'list',
           'supported_on': ['chrome.*:8-'],
           'features': {'dynamic_refresh': 1},
           'example_value': ['extension_id1', 'extension_id2'],
@@ skipping 595 matching lines @@
     {
       'key': '$4',
       'value': 'http://www.chromium.org/developers/how-tos/chrome-frame-getting-started'
     },
     {
       'key': '$5',
       'value': 'http://www.chromium.org/administrators/policy-templates'
     },
   ]
 }