I'm with texrat and zerojay on this.

As for QA finding all kind or problems in advance.. that won't happen _anywhere_. Where I work we suddenly started to get problem reports on something that had worked flawlessly for more than half a decade on a huge number of installations. Turned out there was an old bug deep down there. However, nothing ever triggered it before. Ever. It must have been tested and verified ok literally millions of times, under varying conditions and on lots of platforms. Then suddenly.. boom. At least in our case it was easy to find then, but that's not always the case. The most difficult situation is when hardware, software and 3party equipment/software interoperation is involved.