Prediction: even if this requires surgery, unlocking inner thought will be used in criminal proceedings to establish guilt or attempt to be used to prove innocence. It will definitely be used unethically in military/intelligence interrogations until the law catches up.
"Hit him with this $5 wrench until he tells us the password" XKCD 538
My first dystopic thought was immigration counters at airports /s
I'm not sure if this would be able to detect the difference between truthful thoughts about actual memories, and intrusive thoughts that could give the entirely wrong impression.
Yet, they still do use lie detectors, even though the things they detect can be faked, or triggered out of personal alarm or offense. So it is entirely possible, regardless.