More seriously, having worked in an undisclosed defence company, we were told that we would be prosecuted if we did this. There were many many security controls in place that prevented this from happening on top of the threat.
Are you able to share any of those security controls? How do you stop presumably well-intended Signal app users from conferencing? Are you talking about cellular signal blocking, or are you talking about avoiding public networks entirely in favor of Sensitive Compartmented Information Facilities (SCIFs)?
More seriously, having worked in an undisclosed defence company, we were told that we would be prosecuted if we did this. There were many many security controls in place that prevented this from happening on top of the threat.