Question In the "Edit the user" page, add this user as unlinked individual record.

in the "Edit the user" page (Control panel / User administration / Edit the user)

Please add the following:
Add this user in the following family tree as Individual (Add unlinked records):
[Dropdown of family trees| v |

And when the admin hits SAVE, let this user be automatically added as an Individual (Add unlinked records). Let there be an option to take me the new individual page.
 

Do you really want to add a lot of people who are not (as far as you know) connected to your family tree?

Personally I require that every applicant for registration shows me how they are connected so I can add their connection properly, or at least talks to me about how they "think" they are connected.

See also my answer to your question about "hundereds of users registering... but not returning".

Not a lot of people.
But I wish it was easier to add people that just got registered.

Sometimes I share QR codes in extended family events like weddings and funerals and I might get 15-20 registrations in a single day. Sometimes it branches out outside my extended family, but I still admit them because their husband is on my side of the family and their kids are also considered on my side of the family and can't say not to her brothers and parents.

So this feature could be very helpful.