How to track requests for non existing users?

Hello,
I have not clear the login of the "facebook request" feature (which.. by the way, seems really awesome).

I am setting up a page for my visitors and users to send requests to their fb friends, but I want to keep track of any sent request and who sent it.
I see that this is possible for already mapped users, but what for non existing users.

Will the component create a new user on the fly when a guest send a request form my site,
or do I have to manually create a step by step process like:
step 1: register with facebook
step 2: send a request

Thank you