pat, allow me to introduce you to the concept of "if it ain't got a PK it ain't a table"
Yeah, but ain't that what MySQL is for??? Data what ain't really relational?
I agree with you wholeheartedly, that containing duplicates shouldn't be a concern, but when I'm doing "rescues" of MySQL databases they are frequently chock full of things that make relational purists like you and I shudder!
If Bhargav posted something about a PK that I missed, I'm sorry. Since I don't remember having seen anything about a PK, I didn't assume that one was there.
As long as that works for you, I'm good with it! I guess I just take a different philosophical approach, but as long as your way works for you and mine works for me, then we're both "good to go" on things!