Fiber networks can't be tapped this way because photons don't generate radio frequency emissions. Of course, none of this means that copper is going away anytime soon. So much is already installed, and people are comfortable with a familiar technology. Besides, both copper and fiber gigabit implementations come at a premium. For all the talk of how rapidly the computer industry changes, some transformations happen less rapidly than others.
Physical connections are one area in which change happens at glacial speed.
For years, pundits have seen fiber-optic networking as a technology of the future. The future is finally starting to happen. Brilliant engineering has stretched the capabilities of copper networks beyond what was thought possible even three years ago, but it's clear that it's downhill from here for copper networks. Although it may be years before fiber pulls ahead of copper as a desktop technology, it's clear that, for all but temporary installations, fiber is the first choice for backbones, servers, and data-intensive applications. The capability of running gigabit-speed networks on copper is great, but in the end, fiber will dominate networks.