The joke is fine, but most of all it makes me appreciate how far xkcd has come since then. It's been awesome for so long, sometimes you forget he ever was a beginner.
Write if(0){ on the back of your left hand and } on the back of your right. Use perspective - or whatever - to put the person between your hands.
This, of course, assumes a person is executable, but as circumstances not limited to but including the French Revolution proved, people are definitely executable.
Curiously, this trick makes the person not be executed, but it also means they can't execute you. Theoretically.