I was doing some testing with remotely wiping an iPad (via the Exchange ActiveSync Web Administration Tool) today and was impressed with how quickly it wiped. From my preliminary research this is because it actually only wipes the encryption key, not all of the data.
However, as soon as I restored my previous backup and let the device reboot, iTunes would begin restoring applications and then the device would reset into recovery mode again. I began to think this was a problem with my backup, so I restored the device as a new device and re-sync’d my applications. Then as soon as I setup email, the device rebooted. Obviously my judgment was clouded by frustration, but, fortunately, a brilliant coworker pointed out that Exchange was probably re-wiping the device every time it connected to the server (hence the immediate restarts on backup restores and the restart right after email configuration).
So, I had to go into the Remote Wipe portion of the Exchange Mobile Device Settings and CANCEL the wipe (that it had reported was successful). Also not that the web interface does not seem to keep any record of subsequent wipes that are successful.
Another important note:
iTunes made a backup with each “restore” of the device and the successful sync of the device and subsequently overwrote my old backups I had hoped to restore from. So, had I not backed up my iTunes backups (in OSX under ~/Library/Application Support/MobileSync/Backup), I would not have been able to restore after I discovered this “feature” of Exchange remote device wipe.
At least I have my iPad back to working order…