For all we know, some of her closer friends might have taken polygraphs.... they have every reason to want LE to get through questioning them so they can get back to their normal lives.
I think the friends have all been very cooperative & helpful.... LE has given NO indication that they suspect any of Casey's friends had any idea Caylee was even missing. One after another.... they ALL seemed to say the same thing.... Casey loves to lie & she never showed any sign that anything was wrong in her life after Caylee disappeared.
They're young, single & have only a casual interest in where Caylee is.... they asked & were told someone's watching the child & that's where their concern ends.... she's not their responsibility.