The vulnerability of a home phone line is great. Often the gray box on the side of the garage is unlocked. It allows easy access to all phone lines. An intruder can easily install a tape recorder in the bushes which connects to this box.
Home cleaners have full access to the home and can easily place a baby monitor behind the office bookshelf. This will broadcast sensitive conversations for blocks.
When we inspect homes we also look for common problems like cordless phones that can be intercepted, home computers without proper hardware firewalls, etc.
The email didn't mention knives or guns but the threat was real.
In addition to protective measures (done by others) we recommended a sweep of the executive's home.
His wife was home when we did the inspection. She especially appreciated our discovery of the cordless phones and baby monitors that could be intercepted for blocks.
Surveillance of a home is often a prelude to an attack. In this case we stopped the continuous flow of self-inflicted eavesdropping information coming from the house.
An attacker parked nearby would not have access to this sensitive information.