Ron, I do not know how to respond to you any other way, but what I have to say should be viewed by all.
D.Trump has caused a large segment of our country to believe that they should vote for him because he will make them secure with a wall. Trained dogs will be cheaper and more effective.
The training of dogs is already done by prison inmates and more prisoners could be utilezed. Therefore the cost would certainly be much less than a wall.
Psychollgical fear can cause dangerous and extreme behavior in people and must be dealt with in order to calm them down so that they feel secure.
Dogs that are trained to attack are not vicious. They only attack the ones they have been trained to attack.
Those dogs which are not trainable would not be used. that is common sense. Certainly the minature dogs would be almost useless to do anything other than warn of the order of explosives.
I believe I have covered all of your objections.
I believe we have a rather unnatural fear in this country largely because of the rapid reporting of anything bad happening and its emphasis in the media to get higher ratings. We all seem attracted to the bad. Hence, most of our fears. While the biggest concern aside from global warming is really the growing schism between the rich and the poor worldwide, the public's attention seems focused on personal and national security. A kind of Orwellian malaise. And, if we get right down to it, most violence and terrorism is caused by people with mental illness.
Now, find a dog that could discern a person with a violent mental illness. That would be something. Unfortunately, these people live among us and are tolerated by most until they suddenly act in an uncharacteristic way and then we want to spend big money on security to protect ourselves from all of these people that we like to consider "different." In some cases, whole countries like Mexico. Meanwhile, we don't worry about Canadians.
Ron