30 feet? more like 30 metres
While your mileage may (and very much will) vary, depending on conditions, bluetooth can relieably connect over more than 30 Metres (that is around a hundred of your feet). My blackberry picks up the stereo in the kitchen from further than that (and starts streaming metal to my wife :) ), even without LOS. Given the trouble I sometimes have to connect to the bloody rental car I sit in, the 30 feet advise seems rather sloppy.