IssueTracker

I test this myself and found the same thing as you.  I posted about it on SO here:
http://stackoverflow.com/a/13465373/150016

I actually thought it made sense that they create a new ANDROID_ID for each user, so I assumed that that is what they intended, but I hadn't noticed that the docs say the opposite.

At this point, they better just fix the docs and not change Android.

It seems there is a contradiction in the docs anyhow...

http://developer.android.com/about/versions/android-4.2.html

states

Beware that if your app requests one of the hardware device identifiers (such as the WiFi MAC address, the SERIAL number, or the ANDROID_ID number), they will provide the same value for each user because these identifiers are tied to the hardware and not the user. Not to mention the other problems these identifiers introduce as discussed in the Identifying App Installations blog post.

while

http://developer.android.com/reference/android/provider/Settings.Secure.html#ANDROID_ID

states

Note: When a device has multiple users (available on certain devices running Android 4.2 or higher), each user appears as a completely separate device, so the ANDROID_ID value is unique to each user.

Im the only user on my device why do i have a unique id? Can you explain thus to me