I'm not personally worried about it happening, but I can get why someone would be. I would think the thieves are targeting easy to access cats, to be quick about it, and ones that pay more based on amount of precious metals used. Some models have much more accessable converters than others. I've only seen one customer come into our shop with a loud exhaust where there was evidence of someone trying to cut the cat out, but that's it. Wheels still seem to be the more popular item to steal, from what I've seen at least. Probably just because they're easier.
I've seen some products that try to make it harder to steal them, but I'm not sure why they can't just cut the cages off too? A friend of mine at another shop shared a pic of one that he made for a customer and my other friend who has junk yard experience replied and said he could get that thing off no problem, so who knows.
They're definitely not all created equally. When I've sold old convertors to the scrap yard, the money you get varies, so finding out if you have a high demand car might be a good start. I've heard that the Prius has a popular one, but feel like pathfinders would be lower on the list.
