Since I'm thinking and typing at the same time, why not write this idea too...
I don't have the feeling that a form will be spammed that fast, but it might be an idea to put a little bit security into the form.
It could be as easy as the option of using securebot. It is used by Akobook and Akocomment and maybe some other components. It's easy and effective.
just thinking aloud (or is it OUT LOUD!

)
J.