I thought i had read this but not sure. Does the Magic band track your steps, like a fit bit? Which would be great for my diet!
It does not track your steps. But there are apps for your phone that will wake up and log a gps location every so often. It gives you a route you can plot on google maps and it calculates the distance you've walked. Runners use them.
AFAIK that tracking is limited to:
[...]
Beyond that, I haven't read anything on Disney using long-range capabilities of MagicBands in the parks.
For large-scale tracking of guest movements, they use video cameras to see where crowds are, and sometimes dispatch CMs accordingly.
At
this website is all of the publicly accessible data on the magicband technology, including the XBRs (long range receiver) and the nature of the VHF transmitter inside the band.
When the magicband is active*, it will wake up every 20 seconds or so and broadcasts a unique hardware serial number. WDW database has your account information attached to that number behind a secure backend. Like a cell phone network in miniature, Disney has enough XBRs throughout the park to receive this broadcast no matter where you are inside the park. Where your broadcast can be picked up by 2 more XBRs, a more specific location can be determined.
When the technology was first announced, before it was fully implemented, there were some comments made about how the magic band means there will never be another lost child. I know for a fact that your geo-location is available to the MyMagic+ network within the park. Based on these comments, I believe that the system database is capable of storing that information for retrieval. But since I've not heard of any feature that uses this data, I doubt they bother, and even if they did it's unlikely they have any way to just pull up your location at will.
*Just an interesting aside - The VHF radio is a feature of a custom nrf24le1 chip inside the band. The chip goes into a deep sleep if unused for several days. But even in deep sleep there is an interupt pin that will recieve a signal whenever the HF RFID chip is activated (entering park or hotel room, paying for something, etc). Getting used this way takes the VHF radio out of deep sleep. It's still sleeps whenever it actually isn't broadcasting its signal. This is how the battery can last so long.