@admintiger: That should not be the case. Browsers other than IE do not recognize the behavior property so they do not download the file at all. Unless you're referencing it in some strange way.

I did some experimenting after my previous post and found that loading pages locally with Firefox, Chrome, Safari or Opera does not result in requests to the server for pie.htc. Even so, server log records clearly show the file being requested by other users where user agent strings identify web browsers other than IE. I wonder whether that might be due to intermediate proxy servers downloading all files referenced in CSS files to ensure that complete file sets are cached.