In the latest firmware (0.92) I have implemented geofencing that will avoid transmission when a Pico transmitter and it's balloon is over the UK, Yemen or North Korea.
I have had a few people ask me about it but have not had time do anything in that area until a couple of weeks ago when Matt Downs - 2E1GYP from Essex in the UK provided me with a working proof of concept C code and the Maidenhead Grids to use. This made the coding a whole lot easier and I have now been able to include it in to my WSPR transmitter firmware.
The change is not visible for the user in any way and there are no setting, it is just hidden in the firmware.
It is only in effect on my Pico transmitters.
Now when a Pico transmitter finds itself in one of the grids inside the geofence it will hold off on transmissions until it is outside again.
There is one exception to this rule and that is if a user has a pico running inside the geofence they can still do test transmissions on the ground with a pico as long as it is connected to a computer and the PC software is communication with the Pico over a serial port.
Here is a couple images that shows the areas of no transmission.
73's from Sweden