I haven't gotten through the entire thread yet, but since this is *extremely* regional, I think I'm safe to say it's not been mentioned:
Where I'm from (at least back-in-the-day), one would use the word 'Please?' instead of 'Pardon?'.
Person #1 "Do you have the time?"
Person #2 (if they didn't hear them) "Please?"
When growing up, we knew never to utter it on vacation or we'd get odd stares and quizzical looks.