Promiscuous mode .

Let me start off by saying I am a newbie. I am just starting to attempt to learn to use this what seems like a wonderful tool. However recently when I use interceptor against myself or my other phone. The phone that I'm attempting to monitor( lack of a better word) will almost immediately notify me that my wifi network has been compromised and then gives me the option of turning off my wifi. Now if I was trying to monitor say one of my children's activities on our homes network wouldn't that be counter productive. If that app can't run secretly or without tipping its self off what is the use of it? It didn't used to do this. I have in the past used this app as kind of a magic trick if you were when friends would come over and sign into my wifi I'd bet them that I could get there password to certain sites. Not once did tip them off that the wifi was monitored. I mean I'm sure they knew but third phones didn't tell them as much. Is there a new setting I'm missing in 2.1 ? Thank you for your help.