Stay off Brexit.
As regards the wireless on the Pi, as will almost all other systems, there is a firmware blob that is loaded on to the wireless chip at boot time. This is closed source, we don't have access, only the supplier of the chip. It is occasionally updated for security and bug fix reasons. Then there is an open source Linux driver that talks to the chip (and therefore the firmware). This is pretty standard across everything - phones, tablets, PC's, laptops, routers, TV's etc.
Although the OSS driver can set up the chip, its doesn't control frequencies. That is done by the wireless firmware. Its also probably that even the firmware is unable to change frequencies to make thing go out of range, and that is likely a HW thing.
What is a possibility is that the wrong frequency range may be selected for the particular region the device is in. Not much you can do about that. The device has to be able to work worldwide, so you need to select the correct region to enable the correct frequency ranges. This is why wireless is turned off until the region is set.
