The sales clerk is correct! Flow should have used better English. This is a warning to all English speaking people. If we do not begin to rally respect the language in our usage, we will loose it! There used to be one language used in most of the western world. It was Latin! Because people didn’t respect the rules of the language and it grammar, it is now a dead language, and has been replaced by a dozen different languages. It you really think about it you will see that the same thing is happening to the English language.