[Neil Jones]

I've heard of some jailbroken Fire sticks being available with streaming apps installed which somehow bypass the app logins. I dare say the changes Disney and Netflix are making may also help them to identify and block such (presumably illegal) devices.

IIRC you can "jailbreak" a firestick in two seconds, you just turn the ADB debugging and "Install unknown apps" options on and that's all there is to it.

All that does is allow you to install any app you like that isn't on the Amazon Store. The most common use for this to get something like Kodi installed (and Kodi itself is not illegal, its what you use it for that can be illegal).

The apps are probably just some custom solution in a wrapper which opens issues of its own, but that's the risk you take with such configurations.