One of the key's to decern intention of a visa applicant is to watch facial expressions. This is much harder to do through bullet proof glass.

My father is a retired FSO officer. He never had a person try to grab him for a denied visa. from time to time he has been offered bribes/gifts/threats to call US Senators. . . .

The biggest safety threat was not from visa applicants but from dangerous situations he lived through: He had a stray rocket shell land on his desk (when he was out of the office) and shells drop in front of his car while driving in Beirut. He lived through miltary coup's in Iraq and Haiti and countless other situations. A person trying to grab him from behind the visa counter was the least of his concerns.