No, and no. The entire business of real life crime 'solving' is some knock-off scooby-doo ass sad state of affairs.

Girl absolutely not

I think it's reliable. If they shove the wire up your ass you'll definitely tell the truth.

Nope and nope.

No, and I will do you one better - I question fingerprints! There is as much interpretation as there is science in fingerprint analysis, and different 'experts' will have different standards for how many points of comparison are needed for there to be a 'match' some might want 13, and some might be cool with 5... plus they have all the same human problems of them commonly working with cops and prosecutors who are totally counting on their buddy to help get them a conviction...

No, and NO.

As far as I know they are not foolproof though in the States they are allowed as evidence at some places. But eyewitnesses are also not foolproof and are allowed everywhere. People are notoriously bad eyewitnesses.

No, concrete evidence and witness testimony not to mention a confession, those should be weighed in on heavily over a polygraph.

No. It looks too cartoon-ish. Even if the device is capable of telling the truth, there's the possibility of false negatives and positives. Plus there's some philosophical discussion over trusting its results, but it's too much for my understanding.

I think it's a well-known fact that they're not fool-proof, and I think they shouldn't be used in court cases, and aren't, at least in the US. (I don't know if it's illegal to use one in a court case.)