Insurance like you guys are talking about may not be available in Argentina. Maybe there's a higher risk of fraud.
I'm a gun owner too, but you have to remember a couple things:
- The mugger is mentally prepared for this, and he has a strategy; he's got the drop on you. If you're not careful about HOW you carry it, it will get stolen.
- Shooting at someone in a crowded city like Buenos Aires is just as likely to result in the wrong person getting shot; not worth it to protect camera gear. I'd have a hard time living with myself after that. I suggest a baton, stun gun, or pepper spray as alternatives to lethal force.
- Instead, focus on your carrying habits. Carry camera bags cross-shoulder, not on one shoulder. Close them up when you're not actively digging in them.
- Be as inconspicuous as possible; don't bring all your gear if you don't need to. For instance, if you're doing candid people pictures in the streets, you probably don't need your fancy bounce flash, big tripod, or fisheye lens. Maybe just a normal zoom or a single prime lens.
- Carry the camera on a strap around your neck or with a wrist strap; not on the shoulder.
- When you sit down to lunch or something, close up your bag, put it under the table, and loop the strap around your leg a couple times.
- This is not what you want to hear at this point, but consider a camera that is very good, but does not look expensive. I've been carrying my Canon S90 for all my city shooting lately. When I'm not shooting, no one even knows I have a camera. Yet, when I am shooting, it is high enough quality to get the results I want. (Canon is on the S100 now, which is even nicer) I use the SLR only when I feel safe carrying it: countryside, wilderness, people pictures in friendly places, etc.
- Limit where you go in the city with the SLR set-up. As a resident, you know where and when it would be the most dangerous to carry it. Avoid those places, or only go to those places with a good point and shoot camera.
- Consider a camera back that doesn't look like a camera bag. I've got a small Domke bag that just looks like a small shoulder bag. There's room inside for an SLR w/kit lens and an extra lens too. I'll just cut the label off of it next time I bring it to the city. (as I said, I use the Canon S90 as my city camera)
I hope that helps!
Let us know what you decide to do.