That scenario. They would start shooting with the marchers on the other side of the fence, as they have already proven they would. And, doubtless there are good reason for doing that: 1) the border definition is left unmolested, 2) the act of invasion is stopped on the invaders side of the border. On the other hand, I like to have things a little more clearly defined with regard to intent. That means that I would have let the invaders breach the fence. Then I would have warned them with loudspeakers and filmed the incident. Then I would have had troops fire a volley at their feet (not even at their 'lower bodies' but in front of them). Then, using volley fire, I would have commenced firing on the invaders at intervals with adequate time in between vollies so they could recover their wounded and retreat if they chose to do so. Failure to stop the invasion is absolutely not an option.
Supreme Court rejects plea for freeze on expansion of asylum seekers' detention (Haaretz)
from the article: Syrian slaughter and Israeli restraint