[en.wikipedia.org]

"United States: Cell phone blocking devices are used by federal officials under certain circumstances. Privacy rights of property owners may affect the policy and application of law within buildings. The FCC may issue a permit that waives the law for private use. For radio communications, it is illegal to operate, manufacture, import, or offer for sale, including advertising (Communications Act of 1934).[9] Blocking radio communications in public can carry fines of up to $11,000 or imprisonment of up to one year.[10] The Homeland Security Act of 2002 may override the Communications Act of 1934.[11]"

And, if the crew is using cell phones for their work, you might possibly be charged with interfering with them.

Earplugs may be cheaper.[www.google.com]