Polygraphs

Should lie detector tests be admissible in court?  How can polygraphs assist police in finding a suspect? When are they misused?

I feel that lie detector tests should be admissible in court because the suspect being polygraphed is made aware and given the conscious choice to submit to a polygraph or not, therefore waiving the fact of permission.  Therefore, the results of the polygraph are able to be used in a court setting as documented evidence.  Polygraphs can help police because, simply put, police re not psychics or mindreaders (except in movies like RIPD) and cannot reach into the suspect's mind and body to determine and pull out a detected lie.  The polygraph calmly acts as the psychic in this case and gently can tell if the suspect is lying, without torturing the suspect physically.  They can be misused however, because some police officers use it as a crutch instead of focusing on the importance of the evidence it can bring up.  Some police officers automatically make all suspects submit to a polygraph, even when there is no pre-evidence that the suspect is possibly lying.