"Did you see her walk? Runway walk. My God is that good. I could watch that runway show."

That was Chris Matthews, the longtime anchor of MSNBC, talking about Melania Trump, who could be our next First Lady. Live. On air. That is, until Brian Williams, himself no stranger to astupid comment, cut to a break.

Matthews should have known better, given he wears a lavalier microphone for a living. But Matthews'creepiness, and the public outcry that's ensued, is a reminder for everyone that someone, somewhere is listening. Your mic, as it were, is always on.

TV and radio interviews are obvious. When someone literally pins a microphone on your blouse or tie, somebody -- even if it's personnel in a control room -- is listening. 58003 Just ask Casey Kasem and Bill O'Reilly, if you don't mind an f-bomb or two in reply. The cameras don't have to be on for you to be exposed. That famous Naked Gun scene where Frank Drebin's bathroom experience was heard live at a press conference, happens all the time in television, though it isn't broadcasted live.

Even when your mic seems off, it's on. Bill Gates, the former CEO of Microsoft, gave an otherwise humdrum interview with Bloomberg Television reporter Dylan Ratigan back in 2000. After the cameras were off, Ratigan asked whether Gates would be willing to open-source the code for Windows product in order to settle the massive antitrust casethe U.S. government brought agains the company. "Yes," Gates told Ratigan. "If that's all it took." It was an incredible admission, made in a moment Gates assumed wouldn't matter to the press since the cameras were off -- an admission Microsoft pR would spend a great deal of time and effort walking back.

Microphones are recording us almost every minute of every day, particularly in business.Conference calls are the most visible example.Most call softwareis imperfect in tracking who is monitoring, and almost all calls can be recorded. A few years back, the CEO of Encana, a Canadiannatural gascompany, was asked a pointed question on an investor conference call. After the answer, an Encana executive muttered, "f**king a**hole," for all the call to hear. Former Atlanta Hawks general manager Danny Ferry, in relating a scouting report of player Luol Deng, was recorded on a conference call saying Denghad "a little African in him. And I don't mean that in a bad way." The release of the recording led to Ferry's suspension and firing.

But you don't even need a physical mic to have a figurative one ruin your day or career. people overhear you every day. Ask any judge and he'll tell you of an instance where he had to dismiss a juror or declare a mistrial because someone was overheard talking about a case in a cafeteria or a bar. Famously, in the lead-up to the D-Day invasion, Gen. Henry Jervis Friese Miller was overheard during a dinner complaining about logistics for the upcoming (and top secret) invasion. A lieutenant nearby heard the conversation and reported it. Miller was sent packing back to the U.S. and busted down to colonel, even though he was a close friend and West point classmate of Gen. Dwight Eisenhower.

Social media has made the impact of overheard conversations worse, since people can hear something, then amplify it to their own audiences. Two developers at a conference in 2013 were overheard making jokes about "forking repo's" and "big dongles," which no doubt passes for coder humor but offended another attendee, who posted their faces on Twitter, leading to one losing his job.

And, you really can't trust anyone to keep what they hear to themselves. That seems especially true of spouses. One man was charged for insider trading after hearing his wife talk on the home phone during a meetingabout a pending acquisition for her company. The husband of former playboy CEO Christie Hefner was charged with trading five times on information he gleaned from his wife -- even after both she and playboy's general counsel received assurances from him that he would keep everything confidential.

58003 For all the benefits of honest and authenticity, you're almost never going to get in trouble for what you don't say. It's when you say something that you shoudn't -- a racy remark, a dirty joke, a trade secret, and, more often than not, the unvarnished truth -- that you put your personal and professional reputation at risk. 58003 It only takes a momentary slip of the tongue to have people question your entire morale framework, and that can dent your ability to lead.

The good news is that, unlike Chris Matthews, most thinking people who walk upright in the world put their guard up when someone clips a microphone on them. That caution is a great defense instinct. But, sadly, you can't ever let down your guard -- not to a spouse, not to a business partner, and certainly not to the media. Your mic is always on, and it's ability to create noise in your life is more powerful than ever.