Prevent People Creating Account From Front End

My workflow:

- photograph multiple employees at one company
- send the gallery to a single contact
- that contact is free to share their login (email / password) with their colleagues who can mark photos as favourites, then when all complete the single point of contact submits the gallery using a submission form.
- I go into that person's account and download a list of their faves and import to Lightroom

Despite making my instructions clear, we always get a flurry of people attempting to create accounts in order to log in to see the photos (where instead they should use the login details of this single point of contact).

Generally these are executive board directors, don't have time to read emails, and probably get annoyed they cannot then select photos themselves!

So I am asking for advice here:

1) How do I prevent people creating a new account from front end? This is something I always do for my clients, so there is never a requirement for them to do this, in my case.

2) This workflow was the best possible way to work given my very detailed investigations into Sytist a number of years ago (probably 4). Have any new features been introduced that might alleviate the above problem?

3) Ideally I *would* like an option for employees within a company to create their own individual accounts then select & submit photos, but presumably that's not possible unless there's some way to match their email domain to the gallery (to ensure they can't see other companies' galleries), is that correct? OR an option for the person who hired us to administer access to the gallery themselves... the key being simplicity on that one. Does any such function exist?

4) Sometimes I get gallery submissions from colleagues (i.e. NOT the point of contact in the company but their colleagues), who are signed-in with the email address and password that was given to the single point of contact. But obvs this isn't the *final* submission containing photos of all people. I use a simple contact form for this submission. Is there a way I can direct them to a webpage or message saying "please confirm you are person xyz, the company's photography contact, by ticking the box below, to proceed to the gallery submission page" or something like that? 

5) Any other ways of working that you can think of?

Create account is on or off, no way to have both. it's in your menu set up. green on red off.  and turn off account creation in check out payment options scroll down. Tim will answer the rest, but besides using keywords or passwords and activate find my photos, no way else to seperate photos per person.  Each person would have to sign a contract you send them.

Okay so I have disabled account creation:

but that does not prevent people from seeing the link to create a new account when they click on a gallery link:

I cannot even hide this in CSS, as there's no unique identifier in the HTML tag...

Right now, we have CEOs and Directors etc. wasting their time signing up for an account, only to find they cannot access their gallery. Admittedly they aren't reading our instructions properly, but still want to solve this one.

To clarify: I create user accounts myself on behalf of the client. I do not use gallery passwords (i.e. so anyone can access the gallery under their own account), as the process of proofing / selecting images needs to be centrally managed by the single point of contact. When that person confirms all people have selected photos, he / she submits this at a single point in time.

Please help!

You will have to wait for Tim, I do not see a create account anywhere in the gallery when I have both removed account creation and disabled it in the MENU.