My base uses the speechless code during most of our TRUCE sessions. We have our own target aircraft and combine speechless with NCNG and simulated emergency to short-pattern emergency SRA. We work our ATCOs pretty hard. The hardest thing is not to reply so I pull the mic plug out. After the code is explained the first question should really be 'is this a practice?' !
Clearly chevvron likes to get the occasional . . . . for homing. Maybe his new LARS trainees would like some out of the blue?