Could this be a FCC 15.3.c restriction due to their approvals, or some European equivalent thereof? For information, that clause provides an exemption for
Digital devices used EXCLUSIVELY as industrial test equipment, commercial test equipment, or medical test equipment. “Test equipment” includes devices used for maintenance, research, evaluation, simulation, and other analytical or scientific applications, in areas such as industrial plants, public utilities, hospitals, universities, laboratories, automotive service centers, and electronics repair shops. Devices designed for home use, such as consumer blood pressure meters, bathroom scales, and digital thermometers, do not fall under this exemption.
I think there's some wiggle-room under 'designed for' home use, but I can imagine legal types not wanting the gun, rather than having to dodge a bullet.