Thats why I mentioned the 'myth' of privacy. I wasn't talking about the technology, I was speaking to liability in giving away the locations at both ends of the conversation and how to best mitigate that issue (liability).Even that doesn't hide your location. In about 5 minutes, I could largely triangulate on a particular listing's location to within a couple hundred yards. Once I get a distance from 3 different points, there is only one location on the surface of the earth where that distance works from all 3 points. You could further refine the location by taking additional points.
Technology is the easiest part but.. throwing in an approximation for the distance (random +/- 1 mile even) would make your approach much more difficult, without reducing the effectiveness of the approximation, all you are communicating initially is a proximity, not a location. You could also easily say 'within 20 minutes' or any other reference, again, its not about technology.