They also sell devices called Data Security Protocol Switches (DSPS) which completely prevent your method from working.
"A Signal Proximity (SP) option means that any registered AutothysisDSP computer hard drive that leaves the vicinity of the DSPS signal will automatically self-destruct. This protects against theft and someone walking out the room with a computer. Likewise if a jamming of the DSPS signal is tried in an attempt to thwart the security protocol the registered DSPS hard drives will self-destroy."
Ok, now I wonder: couldn't you harass people using this technology by jamming the DSPS signal until they give up on it and choose something else? I bet that these hard drives are costly enough so that it becomes a problem fast.
The people who use these devices fall under two broad categories: those who operate within the law and those who operate outside of it. In the former case, any jamming can be solved by a call to the FCC to the effect of: "Someone has been operating a jammer near our office. We think it might be a van parked nearby with the license plate 123456." In the latter case, any jamming could mean that the authorities have caught on to them and that they should start destroying all physical evidence. The drive would serve as a canary, so to speak.
"A Signal Proximity (SP) option means that any registered AutothysisDSP computer hard drive that leaves the vicinity of the DSPS signal will automatically self-destruct. This protects against theft and someone walking out the room with a computer. Likewise if a jamming of the DSPS signal is tried in an attempt to thwart the security protocol the registered DSPS hard drives will self-destroy."