Yes. You are right, future Gadgets can watch your Brain and guess your Thought. Measure how your Brain encode Information and thoughts. So you have some kind of an interest to not use that Hardware or to understand how it works and try to code open source tools for everyone.
We have to do something about that, i just try to blow the whistle before every company put not, but some kind of mind reading equipment to our daily life.
Come one buy and code some open source Thought-Keyboards based on EEG and Brainwaves Data. We need it. Cause technology move faster than our thoughts.
P.s: We have many EEG Devices in our daily work shift. Like Helmets to see if we are tired or our focus is not there… and it will be more and more, like the Smart Speakers in our Rooms or some Smartphones in Pockeds or modern Cars in our Garage.