Heh. Does it distinctly state whether the alarms will be sounding in the store or on the device?
Pretty easy bit of code to write to do that.
Edit: Also, with the base station at the back of the store, you know what the signal strength will be - these devices support 802.11AC, so also support the 802.11v feature "time in flight" - so they should be able to state distance from the base station - you get out the front door, the employees are also alerted.
How does that work if someone turns off wifi and Bluetooth? Any risk of triggering false alarms as a prank or accidentally?