Here's some info I found on the legality of jamming and blocking..lol Proceed at your own risk...lol
http://wireless.fcc.gov/services/cellular/operations/blockingjamming.html
The operation of transmitters designed to jam or block wireless
communications is a violation of the Communications Act of 1934, as
amended ("Act"). See 47 U.S.C. Sections 301, 302a, 333. The Act
prohibits any person from willfully or maliciously interfering with
the radio communications of any station licensed or authorized under
the Act or operated by the U.S. government. 47 U.S.C. Section 333. The
manufacture, importation, sale or offer for sale, including
advertising, of devices designed to block or jam wireless
transmissions is prohibited. 47 U.S.C. Section 302a(b). Parties in
violation of these provisions may be subject to the penalties set out
in 47 U.S.C. Sections 501-510. Fines for a first offense can range as
high as $11,000 for each violation or imprisonment for up to one year,
and the device used may also be seized and forfeited to the U.S.
government.
Passive blocking is not illegal yet, but that could change in the
future. Also, there are many illegal jammers in use:
Everyone's Jamming Cell Phones | Techdirt
Mobile phone signal jammers are illegal in the US, but that doesn't
mean they're not used. They're apparently increasingly common, and are
expected to spread quite a bit in the near future. The FCC says that
using a jammer is considered "theft" of airwaves, because that
spectrum has been allocated as property to a commercial entity. The
writer of the article wonders, though, about "passive jamming" - such
as putting up buildings made of material that block out cell phone
signals. While some don't like the idea of having their signals
blocked - others think it may become a lot more popular in the future,
if only to have areas to "disconnect". The article points to the rise
of camera phones as a "bottom up surveillance society" as a reason why
we might want areas that have no signal. That makes little sense to
me, since anyone using a camera phone can still snap the picture, and
then just upload it later when they're in range of a signal. Still, it
will be interesting to see if anti-jamming equipment becomes popular.
Most people have no idea if a jammer is being used, since it just
looks like there's no service. This makes it very difficult to figure
out if someone is using a jammer, and means that no one's getting
caught using these things right now.
In this same article I found this interesting claim:
Block, don't jam, and be legal
We wish we could build powerful jammers that would stop cellphone use
in restaurants, theatres, even around where we are driving, and while
technically possible, these devices are quite illegal in the US. There
is a way to stop some annoying cell phone use that is legal, however,
and that is to block the signals from ever getting to the cell phone.
Blocking is legal because it is just shielding and doesn't interfere
with any users external to the shielded areas. Hospitals, aircraft,
even Dunkin Donuts, can be shielded with simple metal structures that
are designed to enclose the signals from or to the cell phone. We have
developed a simple, passsive and legal shielding system that can be
used to block signals at certain times, such as during an
intermission, or at a meeting break.
For further information, visit
Ambit Corporation - Nanotechnology, Antenna Systems, and Pressure Devices
-- Bob Crowley
not that i care that they are talking to people in the bathroom, but the fact that we only have one bathroom and if stupid wants to have an hour long convo in the bathroom, i have to wait 
but with guys, there's no question. If he goes into the stall, someone's gonna pay through the nose..................literally! 
