A guest lib is a little something-something to entertain your guests and create a memento you can store forever and cherish in your future together as husband and wife.
Place guests libs at the reception where guest can easily grab one to fill in, or even easier, place at each seating with a pen / pencil for them to fill in the blanks.
Before guests leave the reception to head home, have a designated area for them to place the completed guest lib (specified on the lib itself).