I have been using the Get(PersistentID) function to "hardwire" certain iPads to a POS system so that users don't have to login/re-login.
It works quite nice I log the ID when the iPad first connects, then I set up the server/database and user credentials the iPad uses to logon to the system.
Only.... PersistentID is not that Persistent.... It does change when you reinstall fm GO. Which I can imagine and is manageable. I use Apple Configurator to roll out the iPads, so most of them are "locked" and only setup to do one task.
But I had one iPad that was connected to a database for about 3 weeks (the iPad only goes to sleep and wakes up, it's not used for anything else, so fmGO just reconnects the whole time). It was working in the morning then when woken after a sleep, the PersistentID had changed... GRRR. So I had to setup the connection again. I wonder what triggered the change in PersistentID?
I really miss the MAC address capabililty as that would have been handy in this case.
I am thinking about sending a small ID file to an iPad and use that as a key, but that's not really secure either cause people could mail it around.
I would like to ask what other users experience are the Get(PersistentID). I understand from old posts that older notebooks sometimes get the same ID. Also think about other methods to create a unique hash for a device..., maybe just hide a file somewhere?