perhaps i misunderstand it, though must 'resonance' be audibly acoustic, and would a SCIF actually defend against "vibrations" at all frequencies.
the question highlights how ill-suited the 'spy agencies' are for conducting asymmetric anything. Unless they had a Brain inside think of a mechanism and explain it to an Engineer to propose to a Facilities Security Manager who obtained confirmation from a Director, they would be vulnerable. For instance, TEMPEST security - every SCIF has it because inside it was well documented/implemented. SEISMIC security - no SCIF*** is isolated from seismic vibrations modulated with data. So, to ex-filtrate data, have those passing circus elephants stomp their feet in predetermined patterns. Or make one of those "Dune" style thumpers. The worms in this case being .... ? *** I'm suppose some very few SCIFs are vibration isolated for various reasons, but not as an exfil channel. -daniel