How to prevent Prey from being removed
You can enable restrictions for deleting apps, which will require a password to be entered in order to delete any app on your phone. To do this, go to the Settings app on your device's home screen, tap " General", scroll down, tap "Restrictions", tap "Enable Restrictions", create a four digit passcode and enter it again when prompted, and then toggle "Deleting Apps" to OFF.
Prey won't create short-cuts or icons on the system, and can only be found in its install folder, which you can hide by right-clicking on the folder, selecting " Properties" and checking the "Hidden" box. You will also not see Prey's name on your tasks manager.
Although we can't make Prey survive a factory reset, for this we suggest keeping a guest account that thieves can check and lure into, thinking they can find useful information. Even if they end up formatting the computer afterwards, it will give you some extra tracking-time.
Linux, and Mac OS X
Prey doesn't create any icons or menu items so it is almost impossible to detect. Now, we encourage you to add a BIOS password and disable booting from removable devices on your PC, so that thieves will be forced to boot into the existing OS installation and thus not be able to format your hard disk easily.
There’s a firmware password utility on Tiger / Leopard Mac OS installation DVD (look for it in in Applications/Utilities). On OSX Lion you'll find the utility by booting from the recovery partition.