You can't prevent this. I'm glad to know, however, that I'm not the only one
who suffers from this problem :>)
The first thing I did to combat the problem was to setup the guest book to
e-mail me with entries. Unfortunately, that meant that I had to filter
through the spam and manually upload legitimate entries. Too much
maintenance.
However, they are *automated* entries. So I realized that if you change the
file name of your guestbook, the entries will go away for a while, until the
day that someone catches on and your Guest Book makes its way to another
list. I started out with the file name "guest_book.htm". Then it became
guest__book.htm, then guest___book.htm. Whenever I get to the point where I
can't stand the spam anymore, I add another underscore to the fle name and
it goes away.
Unfortunately, this is the only way I've figured out how to combat this
problem.
Viken K.