Feb 16 2018 12:17 PM
You shouldn't have to reject submissions, you should be able to block someone from submitting at all if they're outside the organization. In your Form's settings, there's a toggle for allowing access outside the organization, just turn that off.
Feb 17 2018 03:08 AM
Feb 19 2018 06:42 AM
I'm afraid I don't completely understand your question, but I'll take a stab at a couple things--in the same image I posted, there's also a toggle for blocking multiple submissions from the same organizational users. If you're looking to block multiple responses from anonymous users, I don't believe that's possible--even if there was an option for it, people could game it with incognito/inPrivate anyway.
Feb 21 2018 10:16 AM
I don't think you'll be able to block the same anonymous user from doing multiple submissions. While I see a couple cases why that might be useful, there's no reliable way to force this to occur.