Not wishing to argue for the sake of argument, or seem rude, I'm willing to accept no-one here is going to help on this now due to the rules but....
Neither a private user or the forum would be sued for such information, Renault would not bother sueing for giving out information that defeats their 10 year old security features as it simply wouldnt be worth their while. And a private user may claim the info was used to get their car stolen, that would have to be proved as the only source of the information and they would have to be nuts to try to sue over a car worth <£1000, it's financial suicide. In every case so far of people on forums being sued it has been for libel, is in countries with odd laws AND ultimately they have not been successful. It really is a case of paranoia, however I can see why people are paranoid. If it were a brand new car security system and the forum poster had posted it maliciously to get cars stolen or reduce profits of a business then yes, it would be more likely, but still highly unlikely!
Ultimately, if you fear being sued you should not post any advice on any forum, by your own thinking - any info with which someone injurs or kills themselves, or any negative comments about a product is open to the same risks as the sort of info I'm after.
Anyway, since they're the rules here I'll stick by it, no problem - I just missed that point when I signed up.
Would it help if I just asked for diagrams of the unit, rather than mentioning the immobiliser