There is already a safety on the trigger from glock. If this can be magicaly turned off and the trigger pulls itself, how does another manual safety on the trigger change anything.
This safety is actually less protected by the trigger guard. If human error can defeat all 3 already there then it just takes a tad more negligence to defeat that 4th.
These guns dont just go off. They fire when someone pulls the trigger and that person sometimes blames the gun. This is just something else to blame when the gun handler is irresponsible.
I also think this is foolishness. I really think you shouldn't carry a glock if you cant be safe with it in its stock form.
If you can shoot yourself in the foot with the stock gun, who is to say that you wont turn this safety off and then shoot yourself in the foot. Its equally as negligent.