Out of curiosity, which AV company do you work for? I want to make sure I never recommend that anybody purchase your products. Any software that exploits security flaws in OS or other system-level software needs to ring every alarm bell you've got. Sure Stuxnet, et al, target specific systems and hardware that are unlikely to belong to your customers, but Stuxnet's escape into the wild shows that mistakes or false assumptions were made by the designers and implementers. The software may not be intentionally malicious, but it's already behaving in ways not predicted by its authors. Yet you claim that I should just trust them and not worry that their software might be running on my system against my wishes? That's not what I, as a hypothetical customer of yours, pay you for.