Mrrzy:
Well, what is interesting to talk about?

How about, when did the carrot ON the stick become the carrot AND the stick?
I am not sure that there ever was such a change (except in some peoples perceptions). My understanding is that the expression was always "the carrot and the stick", referring to a carrot (on a piece of string) attached to a stick, which was in turn attached to the harness on a donkey (or mule). The carrot seemed close enough that the donkey could reach out and eat it, but it was just too far away. Stepping forward (to get closer to the carrot) would cause it to swing on the string, appearing to become even more attainable, and encouraging the donkey to keep trying to move forward.
Under such conditions the expression "the carrot and the stick" makes sense. Unfortunately, some rationalise the same expression as meaning two separate things, the carrot for reward, or the stick for punishment. Once this alternate view takes hold, some (who know the original meaning) may take to re-writing the original expression as "the carrot on the stick" to make the meaning clear.
As such, I believe the latter expression is merely a back-formation.


My opinion only :)

Cheers
Nigel