Your defense against wireless surveillance,
Cyborg Unplug detects and kicks surveillance devices from wireless networks, breaking uploads and streams. Unlike a jammer, it
only targets unwanted devices. site 
Plug Cyborg Unplug in an area you'd like to defend. Optionally connect it to your router with a cable to ensure it receives updates.
OpenWrt is the giant on whose shoulders Cyborg Unplug stands; a finely crafted Free and Open Source toolkit for building high quality GNU/Linux firmware for a vast array of wireless router hardware. Without OpenWrt, Cyborg Unplug would be very expensive and difficult to develop. Add a donation using the pre-order interface to help the OpenWrt team with their running costs.
Many wireless routers allow an administrator to create blacklists, although generally they are limited to specific devices rather than an entire product. Cyborg Unplug (using FCC (US) and CE (EU) approved hardware) is just as legal, differing only in that it takes a 'direct action' approach to wireless defense: a detect-and-disconnect routine, alarm system and an automatically updated list of devices able to be banned.
Cyborg Unplug isn't designed for use in those cases where there is already strict control over who uses the local wireless network. Rather, it's for those with networks used by many people (school, office, library, bar, cafe) that either give out the password or provide an open network.