With the actual device under test, it seems most likely that they are insecure and cross-customer issues could occur. I see the unit as being aimed at the hobby/electronics enthusiast, so there might be other aspects about the board that are undesirable for production, I don't know, I have never seen one so I can't judge that aspect.
You will need to query this with the manufacturer, it's beyond my remit as a MIT App Inventor Power User.
The possibilities are:
- The boards are already using a flashable chip that can be given a unique ID via a PC based program or special device
- The boards are not flashable but the Manufacturer is willing to make a batch with unique IDs
- The Manufacturer/other can supply a commercial grade board with unique IDs
If you can buy in large quantities I'm sure you can find what you need and probably keenly priced. One tip with that regard is to haggle over the price (input from my wife, she is Chinese).
So, with my App Inventor hat on, I'm keen to know: have you got the prototype to work with BLE_2_RelaySwitch_C.aia?