Want to cite a law about that?
Because I have never seen that exception in any law regarding radio frequencies.
Federal law prohibits the operation, marketing, or sale of any type of jamming equipment, including devices that interfere with cellular and Personal Communication Services (PCS), police radar, Global Positioning Systems (GPS), and wireless networking services (Wi-Fi).
The Communications Act of 1934
Section 301 - requires persons operating or using radio transmitters to be licensed or authorized under the Commission's rules (47 U.S.C. 301)
Section 302(b) - prohibits the manufacture, importation, marketing, sale or operation of these devices within the United States (47 U.S.C. 302a(b))
Section 333 - prohibits willful or malicious interference with the radio communications of any station licensed or authorized under the Act or operated by the U.S. Government (47 U.S.C. 333)
Section 503 - allows the FCC to impose forfeitures for willful or repeated violations of the Communications Act, the Commission's rules, regulations, or related orders, as well as for violations of the terms and conditions of any license, certificate, or other Commission authorization, among other things.
Sections 510 - allows for seizure of unlawful equipment (47 U.S.C. 510)
The Commission's Rules
Section 2.803 - prohibits the manufacture, importation, marketing, sale or operation of these devices within the United States (47 C.F.R. 2.803)
Section 2.807 - provides for certain limited exceptions, such as the sale to U.S. government users (47 C.F.R. 2.807)
The Criminal Code (Enforced by the Department of Justice)
Title 18, Section 1362 - prohibits willful or malicious interference to US government communications; subjects the operator to possible fines, imprisonment, or both (18 U.S.C. 1362)
Title 18, Section 1367(a) - prohibits intentional or malicious interference to satellite communications; subjects the operator to possible fines, imprisonment, or both (18 U.S.C. 1367(a))