Philbiker, you are absolutely right. Not only is the value of a corgi's bark being underestimated, the heart of corgis is being sold very short as well. Corgis are great alarm barkers and often that is deterrent enough. Michael has told stories of how Taylor has become agitated in the night, something just wasn't right outdoors and he was let out to investigate what was afoot.
Where we lived before my husband was doing a brick patio and a fellow up the street offered to help him load up some bricks and then unload them at our house. Ti, my husband's "girl" was in the dog yard when they returned. She took an instant dislike to the fellow (and she is normally a typical Pembroke and everyone is her friend), never took her eyes off of him and even emitted a low growl now and then. MDH took note of her character assessment and got the fellow out ASAP.
In Deborah Harper's
The New Complete Pembroke Welsh Corgi she relates the story of a break in at a family's home. Their Pembroke went nuts barking and carrying on and when let out of the bedroom where she was sleeping with family members; she went charging after the burglar. In the dark, he couldn't tell what size dog had attacked and he went running out the front door, corgi going after him literally on his heels. The burglar ended up running into a tree and knocking himself unconscious. When police arrived, the corgi still had him by the ankle.
I often joke that most of my Pembrokes would bark their heads off if someone was breaking in, but once inside IF the burglar threw the ball for them, they'd show him where the good stuff was hidden.
My Cardigans, however, most of them would guard the hearth. Jesse, my youngest nephew's Cardigan, has always been very protective of him and would come between my nephew and his friends IF they began to squabble, as children are prone to do, in play.
While I know this is probably not what your inquirer had in mind, Pembrokes have also been successfully trained and titled in Schutzhund work. One that I know of also does some therapy visit work and she is a very sound in temperament corgi, not a vicious frothing at the mouth, bite everythng in site Pem.
I don't find the request or the intent anywhere near the realm of the absurd, just in line with a part of their original duties as all-round farm dogs in Wales. Now the "free" part, maybe not realistic, but other than that I find nothing out of line in the request. The mother has corgi experience, is active and the right corgi would offer her companionship in addition to a little extra security, if nothing more than a good warning system.
Debbie