Okay but how about using this in conjunction with polygraph for some high stakes case where you'd benefit even if you can have slight confirmation of truth. then interrogator (for lack of better word) can structure questions such that you lean the conversation towards truth.
In fact now that I think about it, even 'pleading the 5th' can be worked around using this type of setup.
In fact now that I think about it, even 'pleading the 5th' can be worked around using this type of setup.