Xbox One Screen Time when not Signed in

To play games on the console and use most apps, you'd need to have an account logged in, so what I would recommend doing is going to your Settings on your console and choose "Account" and then Sign-in, Security & Passkey https://support.xbox.com/en-US/my-account/manage-account/change-signin-preferences
Change the settings there to lock-it down or a custom setting you're comfortable with. You can also restrict certain apps for the account on the console or in the Family management page on account.microsoft.com

Locking the console down in the Sign-in, Security & Passkey settings should prevent users from using apps or games without an account to verify usage.

The two Xboxes that are on your account are probably yours and the one that your sons is game sharing with if he put the account on that other Xbox.

What shows up on that screen is any device including Xboxes that the account has ever been signed into.

Screen time goes with the account itself no matter what console it is on so even if the other console signs in with the account they should not be able to use his account.

So even if he were to sign in under his friends account on the xbox it would not show up as extra screen time under his profile.

One thing you may want to check is this.

When his screen time runs out it will ask for a parents permission to continue and require that the parental account signs in and if you have the parental account set to automatically sign you in on the console he may not have to put the password into the
parental account to get extra time on the xbox.

Hi there,

To set screen time limits for your child on Xbox One and Windows 10 devices, go to https://account.microsoft.com/family and sign in with your Microsoft
account. Then:

• Find your child's name and select Screen time (screen time limits are not available on adult accounts).
  
• If you want to use the same schedule for all devices, switch Use one screen time schedule from Off to On. If you’d rather have separate schedules, scroll down and
  switch on screen time for PC and Xbox One individually.
  
• Set how much time your child is allowed to spend with their devices each day, and when they can use them. If you want to give them the full amount of time you’ve scheduled, select Max scheduled. For
  example, if you’ve allowed screen time from 8 am to 8 pm, they could use their devices that entire time.

Tip: Give your kids a heads up on Xbox when their screen time is running out:

• On your Xbox controller, press the Xbox button.
• Select System > Settings > Preferences > Notifications > Xbox Notifications > System and
  select System notifications on. Screen time counts down when a child is signed in, so if they’re not actively using their console, have them sign out.

I hope this helps

• To set screen time limits for your child on Xbox One and Windows 10 devices, go to
  https://account.microsoft.com/family and sign in with your Microsoft account. Then:
  
  • Find your child's name and select Screen time.
    
  • If you want to use the same schedule for all devices, switch Use one screen time schedule from
    Off to On. If you’d rather have separate schedules, scroll down and switch on screen time for PC and Xbox One individually.
  • Set how much time your child is allowed to spend with their devices each day, and when they can use them. If you want to give them the full amount of time you’ve scheduled, select
    Max scheduled. (Example: If you’ve allowed screen time from 8 am to 8 pm, they could use their devices that entire time.)
• Tip: Give your kids a heads up on Xbox when their screen time is running out:
  
  • On your Xbox, press the Xbox button on the controller
  • Select System > Settings
    > Preferences > Notifications >
    Xbox Notifications > System and make sure
    System notifications on is selected. Screen time counts down when a child is signed in, so if they’re not actively using their console, have them sign out.

Set up screen time limits for your child
Applies to: Microsoft account

• To set screen time limits for your child on Xbox One and Windows 10 devices, go to your family group and sign in with your Microsoft account. Then:
  
  • Find your child's name and select Screen time.
    
  • If you want to use the same schedule for all devices, turn on Use one schedule for all devices.
  • If you’d rather manage the schedules separately, scroll down and switch On or Off individually for Xbox One and Windows 10. If you don’t want screen limits at all, turn the same option Off.
    
  • If you want to give them the full amount of time you’ve scheduled, leave the default setting of Max scheduled. For example, if you’ve allowed screen time from 8 am to 8 pm, they could use their devices that entire time.
  • If you don’t want the default Max scheduled, select the row for each day to set how much time and when you allow your child to spend with their devices.
  • Type in your schedule choices, select Add and then select Save.
• Help your child get the most out of the screen time
• Have your child sign out if they’re not actively using their console. Screen time counts down only during the time a child is signed in.
• Give your kids a heads up on Xbox when their screen time is running out. On your Xbox controller, press the Xbox button. Select System > Settings > Preferences > Notifications > Xbox
  Notifications > System and select System notifications on.