is the accept list easy to bypass?

Hi, I plan to use smartlist for a announcements only list, where only a person will be able to post to the list. From the manual, I uncomment force_submit, delink the accept file and put in it the authorized email address for posting. I wonder if this method is not too easy to bypass by a malicious subscriber. It seems enough to configure any email program with the posting address to spam the list (and I'd say this address is sent in the headers). Am I wrong? If not, what can be done to avoid this without making the list moderated? TIA, Llorenc Sole Maresme Netcom, S.L.