If this is for you macro security can be set to low under
tools>macro>security (I wouldn't recommend it though). if not for you it is
up to the users, if they have it set to high it will not run at all
The users can also choose not to run macros when they open the file. I
suppose you could sign the macros somehow so that the message wouldn't come
up. I've only done that with my own files because I'm tired of the message.