if you were going to "pause/unpause" registrations to your app would this be a sensible solution: 1 .Keep registrations actually open so you can capture leads 2. Add after registration hook to check if sign ups are open (this is before after registration 'session' hook) and stop flow there 3. On login flow add before hook to check if sign ups are open and stop flow if so

Yes I think that makes sense. Are you using a custom UI? Then this should be easy to implement on the UI side as well. With the Account experience you would still have the link to sign up on the login page.

its a custom ui