No, dealer wasn't concerned about safety. He said it might just be "free play" in the U-joint. They went through and made sure all the bolts/nuts were torqued to spec. Mine does it more often (or maybe I just hear it more) at low speeds (parking lots, mainly). Changing the mode has no effect, but I always leave mine in "comfort". Mine is hardly 3 months old with 25,000 miles. So far, no oddities other than the noise itself. I don't think it's a safety concern, more of an annoyance....kind of like I can't plug my iPhone in to charge without it automatically switching to play my music, starting alphabetically. That is my biggest peeve with the car. I'm thinking about recording an MP3 with no sound and titling it Aa, just so I don't have to hear it start playing music EVERY TIME!!
Edit: My dealer specifically listened at each strut. It is NOT coming from the strut....at least on mine. I verified this as well, as the dealer turned the wheel. It is somewhere between the column and the rack itself, possibly within the rack. I think it may be hitting a heat shield somewhere, personally, but I can't find anywhere it might be doing this.