Indeed, practices like Extreme Programming (what a silly name) engender a zero liability situation. Of course I doubt that anyone strictly follows the guidelines involved, but it certainly helps. Your firm's laudable practice of strict control doesn't really exist at certain places. For instance, Microsoft's guidelines suggest not testing allocated memory if it's NULL in the production version of an app -- the exception catching system will grab it, right?
Regardless, the lemon laws can't hurt anything that is free as in beer. As was pointed out earlier, the GPL is a gift, not a contract -- it gives you rights, dependent on certain conditions. Someone else mentioned it being in a perpetual beta; that, too, is insurance, though not everything is unfinished.
The lemon laws will serve more to deter advertising scams and false claims. For instance, if Microsoft said that Access is enough for all database needs (which it has the sense not to), a hopsital could then sue them when it crashed and muddled up records. MySQL just says "I'm a database, look at my tested statistics and my source code -- decide for yourself."
Mike GreenbergThe moon may be smaller than Earth, but it's further away.