It's worth clarifying, our work at Backyard Brains is strictly educational. We do not create devices that are designed to treat, detect, or diagnose disorders or severity of disorders. Consequently, we do not give or speculate on medical advice.
The principal elements of our experiments are: recording EMG & other signals and sending functional, electrical stimulation. On one side of the circuit, we record the electrical activity of the controller's muscles, then we use that electrical signal to directly stimulate the muscles in the other participant. The signal to control the muscles is generated initially in the brain so this experiment is focused on the nervous system at large, and not the brain directly. Furthermore, a muscle or nerve (whether alive or dead, as we see in experiments like these) cannot "resist" or ignore the electrical stimulation - it isn't a question of psychology, it is a matter of physiology.
I hope you find this information useful. Thanks for reaching out: curiosity is important, and informed, citizen scientists, are crucial to an educated and advancing society, especially as we collectively work to better understand, treat, and someday cure neurological disorders.