Exceptions to "Thou Shall Not Kill."

We were having a discussion in humanities, and by the title of this post... of course it sounds heavy and serious. haha. It really wasn't. At least, not too much. We were talking about how the fact that there are exceptions proves that there is a rule. In apologetics, its hard to get past the moral argument, because everyone in the world has exceptions to the same moral law.

For example, one of our exceptions is war. It isn't considered murder to go out and kill people in the heat of battle.
Another exception is self-defense. If someone is coming at you with a huge butcher knife intent on stabbing your brains out, no one will put you in jail for defending yourself and killing them.
Capital punishment is also a socially acceptable exception.

And then... one guy in the back raised his hand to add an exception to the list. You know what he said?
Trespassing in Texas.