You can get started with system or PlayStation Network features quickly and take advantage of remote queuing if auto sign in is set up.
However, this means that your account may be easily accessed by others who have access to your PlayStation system. Therefore, there are certain situations where you should not have auto sign-in enabled.
There are two accounts that you can sign in to on your PS Vita; the local user account, which is the user on the PlayStation system itself and the PlayStation Network account, which can be linked to local user accounts on different activated systems for playing online, making purchases from PlayStation Store etc.
You can only assign one local user account to your PS Vita at any one time. This means that the PS Vita will automatically log in to this user when it is switched on. Auto log-in to local user cannot be switched off.
The PlayStation Network account assigned to the local user account cannot be changed after it has been chosen. Once your local user account is signed in to PlayStation Network, it stays signed-in in the background and automatically signs back in when you switch on your PS Vita, even if the system was switched off completely.
This means that any user with access to your PS Vita can also access your PlayStation Network account information.
Sign out of PlayStation Network at the end of every PS Vita session to stop others accessing your account by going to [Settings] > [PlayStation Network] > [Sign Out].
There is no option to save your password so signing out will ensure that no other user can access your SEN account from your PS Vita.
You should sign out at the end of every session on your PS Vita, but be extra careful if any of the following apply:
If you do not have access to your PlayStation system to sign out of PlayStation Network, you can change your password from a web browser. This means that if another person has possession of your PlayStation system they cannot access your account through it.