* Once you create an application, you can set how you want your users to provide their identity. You can ask just for the email, email+digits or just their phone number. However, when you deny a notification from your phone, the user is required to provide the second identifier (email requires additional last 3 digits, phone number also requires email, and email+digits requires the full number in addition) * The system only allows a single login per user, so if you have initiated the request first, somebody else would have to wait for you to finish the request until they can initiate it). There are additional limitations happening in the background that prevents spammy logins to reach the user's phone. * We're still trying to improve our UX, so we might take that in consideration for future releases