Question (spoilers!)
I was interrupted and missed why Demi had the police wire her but then told Alec she was wired.
shareDemi "played the game" of being on Alec's side. She had to side-step Alec all over the place to make sure that she was protecting her son and herself. She'd already had far too many surprises at the hand of Alec.
So she chose to go by her own wits. Alec, by the way, saw that quality in Demi's character and that's what made him trust her and like her.
Flanagan