Specific Devise recognition by APP's

[gordon_s1942]

When our fabulous Centrelink 'Had Issues' recently, I used their APP to access my account and after I did so I found not only is this access limited to THIS devise specificaly but neither my wife or anyone else access their accounts with this devise !!
According to the details, this is done for 'Security' reasons.
Now I can access either mine or my wife's Centrelink account on any computer so why and how do they lock up Tablets and phones to one user only?
I later found this restriction in part this also applies to accessing my Bank A/C using their APP to this specific devise.
I had installed the Banks APP before I did a total Reset when I thought the Tablet had a problem so when I reinstalled the APP, I got a message about the previous installation being cancelled inferring it was on another devise?
I am still trying to work out how to 'Back Up' data or transfer it to another (same brand) tablet should the need arise.

[jwoegerbauer]

Only can tell you how it's the case with an Android tablet:

When you take it in use for the 1st time you are asked to login with your Google account. If you do so, in connection with this account also the WLAN-data are stored. This function by default is activated. It is not mentioned though that also passwords to WLAN-nets are copied. But with Android you always can switch off this password copier.

[gordon_s1942]

This is for an android O/S tablet but if you have the need to use any Centrelink site they now offer this 'access' to Tablet/Phone users.
This 'Individual User' only per devise is in their FAQ section but I dont remember it saying if this applies to all O/S or only Android systems but they state this 'Individual Only' system is for 'Security Reasons'.

Now the APP for my Bank I downloaded from Google Play but the Centrelink one was from their own site.