There are a lot of cars out today with way more advanced encryption schemes on their immobilizers that get stolen because there's enough demand for them. Some unethical hacker breaks the system and then sells a buttoned up version to thieves.
Unfortunately, the same way the ethical people at the ECU Repair place found a bypass and used it to help out Spec Boxster racers, if 986s were as common as Civics, I'm sure someone would have replicated the work for the bad guys
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However, these aren't common enough, and aren't worth that much, so I doubt a sufficiently motivated thief exists
If anything I'd more worried about someone stealing the keys, or taking it while it's running. We've reached the point if "herd immunity" for hot-wiring, most modern cars can't be hot-wired without model specific tools, so if they're trying to steal you car they'll skip straight to trying to get a key or just hauling it away if it's worth enough
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Now more on topic
I saw your post 78F350 and it helped me understand this better. From what I've found, there's two options, mess up the ignition cylinder, or mess up the pin. I'm debating which is the lesser of two evils, but right now I'm thinking the cylinder since I'd rather make sure I can get the entire assembly out before tearing apart my dash than find out after that I can't break the pin out...