According to the patent, they have described “theft conditions” which are likely to involve large-scale movement, such as carrying the device in the hand which will then generate low-frequency acceleration signals. So by instituting a low-pass filter, those low-frequency acceleration signals can then be associated with probable theft conditions which at the same time helps reduce false alarms. At the same time users can adjust the sensitivity of the detection, along with the alarm they wish to have go off when the device has been taken and etc. There will also be a delay between the time the phone detects a theft, which allows the user to enter a passcode to deactivate the alarm.
Of course we expect that there will need to be quite a bit of fine tuning involved to ensure false alarms don’t go off simply by having our phones in our pockets and walking, but it sounds like a pretty legit system especially in snatch theft scenarios where the phone’s constant alarm will help the authorities locate the device.