So if the robber gets a shot off hitting you in the gut that will cause you to bleed out you shouldn't fire back and "deliver retribution to your attacker"? Interesting position.
By all means. just leave the kids in the school on the next block out of it.
And now I'm done talking to you at all, until you start acting sane. Welcome to the ignore list.
So that's how you win arguments? "Waah, you don't agree with me so I'm going to ignore you because I'd rather talk to people who agree with me".
There is a risk that people will get hurt if the bomb goes off, but risk != harm, right? Anything could happen. The trigger could click on the bomb, a divine intervention, anything.
The reasonable response here would be "No, we shouldn't allow people to carry nukes". But you can't say that. Can you?
No, I disagree with many people who are not on my Ignore list. I put people on ignore for being assholes. See my "discussion" with Rarity for details.
Here's how an AnCap society might handle an asshole like you carrying a nuke rigged to explode upon their death:
If you advertise the fact that you are carrying such a device, you will find that everywhere you go, everyone has mysteriously disappeared. You would indeed be completely safe from robbers. And shopkeepers. And traffic jams, so at least there's that. Or, of course, you may be disallowed to enter any area, because the owners don't like the risk of you tripping, breaking your neck, and destroying their property. Either way, good luck getting lunch.
If you
don't advertise it, and someone spots the fact that you have a bomb strapped to you, you will be treated as a terrorist. If you're lucky, they'll simply draw on you and order you to disarm the bomb. Since your only recourse is to do so, or to trigger it, and as you say, it's a defensive system, not an attack system, you'll disarm it. If you're unlucky, the last thing you (and everyone in the vicinity) will hear is "he's got a bomb!" Assuming your defense system does not backfire on you and kill you and everyone around you, you will then be expelled from the property. Once again, good luck getting lunch.
You're welcome to own nuclear explosives. You're welcome to carry them. You are not welcome to arm them and carry them around keyed to your vital signs. That makes you a terrorist, and you will be treated as such.