In the Maching.config file, there is a "deployment" element that you can add and set that will help in this area. Once set, this element will tell the ASP.NET process ignore several security and performance related settings that may have been left enabled inadvertently in the web.config and deployed in a production environment. Adding this element on all of your production servers results in the following:

• The compiler "debug" flag will be set to "false", ignoring all web.config files
• The trace “enabled” flag will be set to "false", ignoring all web.config files
• The customErrors "mode" flag will be set to "On", ignoring all web.config files
• The “ScriptMode” flag of the AJAX ScriptManager and ScriptReference controls will render release versions of the client scripts to the browser while ignoring all control level settings

File: Machine.config

   <configuration>
      <system.web>
         <deployment retail="true" />
      </system.web>
   </configuration>

For more information on the deployment element:
http://msdn.microsoft.com/en-us/library/ms228298(VS.80).aspx

For more information on the ScriptMode property:
http://msdn.microsoft.com/en-us/library/bb344940.aspx

For more information on how and why Microsoft.com uses the deployment element across the enterprise:
http://technet.microsoft.com/en-us/magazine/cc160896.aspx