The idea that the person your forcing to do something (anything) may be armed makes the government less likely to force people to do things.
Sometimes we all need to heed the rules of the society in which we live.
If an elected government cannot make rules because "someone might get shot" then the government needs to control the guns. Otherwise we're all at the mercy of those willing to kill so they don't have to abide by the rules.
Government officials already need to worry about the political implications of their actions, they shouldn't need to worry about being murdered by a loon with a gun who disagrees.
The Universal Declaration of Human Rights says "Everyone has the right to leave any country, including his own, and to return to his country." Australia was violating human rights every time they made it illegal for one of their citizens to enter the country. Don't lump these "illegal border crossing"s in with foreigners trying to illegally immigrate.
Which is a shame, really. I quite like it.