I find that most people don't hear me coming anyway; Mp3 or not. It can be amusing to hear the streams of shocked profanity as I pass and head off into the distance... especially when they come from the so-called "hard-guys"
I've owned Walkmans since they came onto the market in the late 70's; but I never took to running with them. I think that they (for me) somehow detract from the
purity of the running experience (yeah, I know this is likely to solicit many a raised eyebrow and utterances of "Bo*^ocks"...).
...I think that I must be the running equivalent of a Luddite... coming from a running time way back before the present day "aids/crutches" of Mp3's, treadmills, Garmin, Polar, gait analysis, cross-training, and even, er, on-line forums (are we being stifled or even held down by the sheer weight of information available to us?). Heck, there were only a couple of specialist running shoes available at the time... (I remember being taken for my very first pair of proper running shoes. It was a little shop outside Bury. Reebok shoes. I think that some of the shoes may even have been made on the premises!)
Erm... sorry about all that... but I
do get the impression that a majority of people seem to be sadly dependent on technology to influence/motivate them to get out running... (or not, in the case of the seemingly ubiquitous treadmill...).