Just one question, what if the file is serve through a CDN network or any other serverside caching techniques?

I use cache buster only when i want to dynamically load another file that contains dynamic data, this should be a function call from within the scope of the swf, things like loading an xml file that is generated dynamically and or using framework like SWXhttp://swxformat.org needs cache busting. Personally I will not use the cache buster technique within dom level, and i don't think that it is fixing any problem that ie is generating, All i can see is it is doing cache busting with every page load.