Word 2002 -sending unalterable documents

I need to send out a policy document to our staff over the network and I don't want the users to be able to alter it. How can I prevent them modifying their copy and then having a policy around that has my name on it but not my words?
I have tried making the file read-only, and also adding a password to it under tools-options-security so that a password is required to modify it. Neither of these works - all the user has to do is click read-only, modify the document and then do save as , and they can save it locally with different contents. Any way round this?