People getting opt-in freebie without being added to mailing list

I noticed on my SS Analytics that some people are accessing my opt-in freebie page (a non-linked Page which is turned off to Search) but not being added to my Mailing List (or even added as a Subscriber).

I have a newsletter block with reCAPTCHA set up and 'Send Confirmation Email' turned off.  

A person has to click reCAPTCHA to enable the button that takes them to the opt-in freebie page to work.  So how are they getting to that page without being added to my Mailing List??  Shouldn't clicking reCAPTCHA automatically add them to my Mailing List?

Thank you for any help with this!!