I regularly go through security at Manchester.
I take the attitude these people are doing their job and engage them in light conversation. Generally they respond, sometimes they don't, if they don't I shut up and let them get on with their job. If I am selected for a search so be it I let them get on with it. Strangely enough I have little or no problem ever with them.
I would guess if I was doing my job and someone said to me 'it's none of my business' I would be less co-operative.