The journalist is on his own to find out. And of course, he won't. Because the best way to treat an attachment is to trash it unopened. Never send attachments unless a journalist ask for them. Don't be alarmed, that will never happen.
Some people have a habit of sending complete adressbooks along with an electronic press release.
Quite remarkable if you consider the fact that this never happens with paper press releases. The habit is also contagious because others copy this list of email adresses to send out there own mailing. The worst thing however is that it looks rather stupid. Sending a mailing with the adresses of members of the press visible in cc-line is showing off in a pathetic way. Some journalists read your mail on their cellular phone.