When you sign up to Infinite Flight in-app I believe the sign up process should be something like this:
Step 1: Sign up using Google or Facebook.
Step 2: Pick a display name, unique, no spaces, short (required)
Step 3: Pick a password, password protect your account (optional)
Step 4: Acronyms, seperated by a comma (optional) See this request: Add a field to user information for acronyms
The sign in process would be very simple and very similar to the sign up process for the forum or any other website/service you’d join. Just like the forum, you would not be able to change your username (display name).
All users who currently have an account would on restart of their device or update of the app, be promted to choose a display name (required) and password (optional).
If your display name is taken, you would then receive a message “display name taken”.
There would be a page in your settings that would allow you to change your display name and password.
By changing your display name, you risk loosing your previous display name.
I think if users did not have the ability to change their display name, it would greatly help with organization among other things within groups (VAs/VOs), moderation, reports (ghosts), violations, support, ect. because users would be linked to their specific and unique account.