PlayerPrefs saving

I would, if in your situation, build 2 small test apps. Then try to save something in playerprefs from testapp1, and then see if I can read it from testapp2.

If I can read the playerprefs from another app, my guess would be that playerprefs is bound to the device/player and not the app.

Second test would be to try to update testapp1 and then read the first information again, to validate that an update does not hurt data belonging to a certain app.

I havent tried this, but this is how I would proceed without any docs telling me how Playerprefs are implemented on smartdevices.

Update

http://unity3d.com/support/documentation/ScriptReference/PlayerPrefs.html

On Mac OS X

PlayerPrefs are stored in ~/Library/Preferences folder, in a file named unity.[company name].[product name].plist, where company and product names are the names set up in Project Settings. The same .plist file is used for both Projects run in the Editor and standalone players.

On Windows standalone players, PlayerPrefs are stored in the registry under HKCU\Software[company name][product name] key, where company and product names are the names set up in Project Settings.

On Web players, PlayerPrefs are stored in binary files under ~/Library/Preferences/Unity/WebPlayerPrefs on Mac OS X and %APPDATA%\Unity\WebPlayerPrefs on Windows. There is one preference file per Web player URL and the file size is limited to 1 megabyte. If this limit would be exceeded, SetInt, SetFloat and SetString will not store the value and throw a PlayerPrefsException.

But this doesnt say ANYTHING regarding smartdevices. Hmmm... ! My guess from this sentence: "There is one preference file per Web player URL and the file size is limited to 1 megabyte." is that its bound to the app, but just as I can change the unity3D file of a website, so should the App be able to change/update without destroying the Prefs. Thats my bet.