Don't have a rationale, flyboy. It's in the grammar books. I remember it especially because I've gotten it wrong. Sorry I can't offer more than this.
Okay, thanks, Roberta. I forgot on my earlier post to wish you luck with your surgery tomorrow and to tell you that I'll be thinking of you.
Thanks, kid. I appreciate it.
Perhaps the rationale for the comma after etc. in the middle of the sentence is to alert people that it's not the last word because sometimes it is (as opposed to other abbreviations, like Mrs. and U.S.A., etc.)...
