I wouldn't call it common, precisely, but I would expect a reasonable number of people to understand the meaning, although fewer to know the reference or the (somewhat spurious) story about its origin, and sadly fewer still to be able to understand or recognise the original Latin tag "non amo te, Sabidi" if it was used in conversation.
(It's a very delightful tale actually, especially for those like me who are Latin lovers in the more uncommon sense.)
In a bizarre coincidence, considering I was mentioning Heyer earlier today in another thread, I'm pretty sure "non amo te, Sabidi" gets quoted in one of her novels. I'd like to say it was in Venetia, but I'm not quite sure that's the right one. I'll have to check when I get home tonight.
(Am I totally ruining my forum reputation by revealing my fondness for pseudo-Regency and somewhat trashy romantic fiction?)
Student or Learner