NO!

I had an interesting conversation with some friends today regarding the use of the word "NO" and it's uses in dog training, and the conversation was interesting enough that I thought it should be shared.  It started as we were discussing a dog that has a tendency to sniff on the table during an agility trial.  We all agreed that, with the particular dog, stress was the major factor.  It was brought up that the usual tendency for someone who has a sniffing problem, is to utter the word "no" at a trial, and expect the dog to quit sniffing and become MACH  material immediately!  This seldom works.  The conversation regarding the reason this doesn't work went something like this (author retains the right to paraphrase and/or alter the exact conversation in order to make delivery of said message more effective):

B:  Let's play a game of trivial pursuit.
M:  Sure
B:  What piece of a WWII mess kit was referred to as a pus blanket?
M:  Hrmmm.. Bread?
B:  No
M:  Napkin?
B:  No
M:  Crackers?
B:  No

There was a lag in the conversation as we started at B, waiting for more information.  None was forthcoming.
I googled this, and even called my Dad- a career military man- to try and glean the answer to no avail.

So, what does this prove?  I have given my 3 best answers, and have offered other behaviors, and still do not know what the correct answer is.  I also do not have enough information to answer the question.  All I have is "no". 

When it comes to dog training, I'm not about what works, I'm about what makes sense to me.  This makes sense to me.  Dogs learn best (as we all do) when the information provided is black and white.  Simply teaching the dog "no" can make them stop one behavior, but doesn't provide them the information they need to perform the correct behavior, and this can cause undue stress on the dog.