I am with you Blu...
Also LDT's are not realiable...they are used for one reason to break a perp down...get them over the breaking point...create a perception that they are nailed and if they just spilled the beans the hassle will be over.
Why anyone would subject themselves to a LDT is beyond me...why would you take a test that cannot prove your innocence but only be used against you...the grandmother is a perfect example.
CAUTION: HUMOR ALERT
Speaking strictly personal here....I am Catholic, educated by some of the finest ruler-whacking penguins in the world. As such, if I were ever threatened with a LDT, I'd immediately plead guilty...to whatever!!! Once, one of my bosses said he loved to hire Catholic girls, we're always guilty and ready to take the blame for whatever!!:) So, I agree, an LDT is a powerful, if inadmissible, investigative tool.