anyway its also popular to insist chips cannot be run at 16mhz on 3.3v. i suppose it depends on the application and what your business insurance flyer has to say about potential liabilities. in my experience the threshold was closer to 2v for every family i tested.
Well most of us know that one can run our AVR chips at 3.3v @ 16 Mhz, but most of us also know that it is not operating at the AVR datasheet recommendations. For us hobbyist that is fine, but a professional EE designing something commercially for a company would be foolish to operate any component outside it's datasheet ratings.