Letting Guests Know About Registry...

A friend of mine is getting married in August and she and her fiance registered at Target. She told me that they gave her a booklet of tear off sheets that say something like "registered a Target", I dunno. Anyway, she has no clue if she is to send one along with each inviation or if it`s too tacky? I told her I wouldn`t care either way, but I thought I`d help her out and get other people`s opinions also. Or should be just be told by word of mouth where they`re registered?