Thanks to Bruce Schneier security blog, I come across an interesting article about liability and software. The problem is well known

• if you impose liability on any software producer, then it's a dead sentence for free software
• but the current situation enable software dealer to sell faulty software with I can't audit, with liability for them if their software fail on a large scale.

Of course for better security, the solution could be to not use proprietary software, still a law as proposed on ACM could be useful to protect madam Michu.