Handshakes and self disclosure/ Police officer and suspects

Some of you know I use to teach at a law enforcement training center and that I am particularly interested in what body language can make people open up. In grad school I wrote a paper on body language to increase self disclosure and I have been researching that process ever since.

Recently I have been corresponding with a police officer about some of his experiences Here is one of his stories that I thought was interesting.

"After hearing your handshake lesson and reading the article in your book, I started shaking every one's hand I was introduced to. I meet people all day long, but I used to shake hands only about 1/2 the time. I notice now that when you offer it first, usually there's a brief smile on the other end of it- almost like they do not expect a cop to be friendly- it works!"
"Now, when I shake a suspects hand, we have already made inroads into the rapport-building phase of interviewing him. I of course want a confession- or at least an admission from a bad guy to help me make my case...I clearly remember at least 3 times when I was on domestic calls and would not shake a guy's hand. The call would be all but over and we were literally leaving the scene. Me not shaking the dude's hand at the close of "business" would make him mad all over again. Hey it's a tactical consideration, but I wonder if I could have shaken more hands now."

I would love to know what you think. Do you think shaking hands can make people self disclose more? Do you have a story to share?