However, I can't help but feel Ms. Cameron was trying to be even more clever by making a play on the homophonous Entrez vous, which is often used by non-native French speakers to mean "Come in." The problem is that it doesn't. The French verb entrer is not reflexive; the correct way to say "Come in" is simply Entrez. The only time you'd use entrez-vous would be in a question, as in Entrez-vous ou pas ? (Are you coming in or not?) Sorry to be a stickler, but I think even humor should follow grammatical rules.
Lessons: Reflexive verbs | Questions | Homophones | French in English