I called my brother last week, and we had a 30-minute phone conversation. Over the next four days, and unbeknownst to him, his cell phone called me back five additional times.Once I could hear him talking work with a coworker. Another time he was talking with our mother. Two other times, it sounded like his wife and young kids were chatting. The most recent time was notable in that he was having a private interaction that I am pretty certain neither he nor his wife meant to be public.[ The Web browser is your portal to the world -- as well as the conduit that lets in many security threats. InfoWorld's expert contributors show you how to secure your Web browsers in this "Web Browser Security Deep Dive" PDF guide. ]When I called my brother after his last unintended dialing incident, he said that not only had his cell phone called me back several times, but during our original 30-minute phone, he had accidentally opened up another line on his work cell phone. They too had heard everything he told me on his lunch break. Such is the weakness of touchscreen phones: They can't tell the difference between an accidental touch and a purposeful touch.This doesn't just happen to my brother. We all know the feeling upon realizing that our cell phone has mysteriously dialed someone -- again! When it happens to me, I usually have a sick sensation in my stomach, hoping I haven't said anything revealing or unfortunate. It has taught me to never say unkind things about others that I wouldn't say in front of them. I'm fairly certain that in the past I may have said some not so flattering things about the person I just hung up on.The problem of unintended dialing worsened after I got my touchscreen phone, although it happened enough with my regular cell phone. I've had my cell phone dial people (and 411) just by putting it in my belt loop case. I'm so paranoid these days that I manually lock my phone after each call and inspect my call history log to see if I've inadvertently dialed someone.I wonder how many company conversations, work secrets, and personal affairs have been revealed by unintended dialing? Even more thought provoking: What type of feature would be needed to prevent it? I say this because my last two cell phones had features meant to prevent unwanted dialing, but they haven't proven to be 100 percent effective.So let me ask readers to share their unwanted cell phone experiences in the comments below. Better yet, share a cell phone model or feature that can prevent mystery dialing all the time.This story, "Unintended cell phone calls put privacy at risk," was originally published at InfoWorld.com. Follow the latest developments in security and read more of Roger Grimes's Security Adviser blog at InfoWorld.com.