Say that you need a button at the end of a page with "I agree" caption. If it's an Intranet or an Extranet, you'd want to see who clicked on it and at least you'd like to see the timestamp when this has been submitted. However, there is a minor bug - you can't!
As a workaround, just add any other element, but given that you probably wouldn't want something visible, go ahead and add ex. Hidden visitor profiling, it might even be useful, given that you can configure it to collect:
Now, go ahead, submit again and both the first and the second entries are visible.
If you remove the profiling, you are back to square one, no values are visible.
UPDATE: This bug has been fixed, see AFORM-836.