So, you do advocate killing immigrants at the border. Why are you trying to cheat on us you don`t???
I am not a fan of killing in general, but self preservation kicks in when lethal assailants appear. Gloves off then, thankfully against mostly unarmed assailants it makes the easier by not having to use lethal weaponry which also can be cheaper.
Generally speaking, most border guards are tasked with firing back with lethal weapons. It's a general rule, states don't look kindly to uncontrolled invasions. No matter the motivation due to foreign intelligence services.
People are vetted for a reason, even German football tourists were surprised over the harsh security policies put in place in Warsaw. Not knowing the football culture in Poland (even tho Germany is a neighbouring country with easier access of information to Poland/Poles then let's say a resident of Iraq or Afghanistan) still leads to culture clashes.
Ignoring this? Not especially bright I must say, tolerance and political policy of toleration is decrease outbursts of conflict and to have a set of rules for conflicts not to become volatile.
When it first erupts or likelihood of it happening anyways, it's a quite foolish approach.