Linda's demo is merely showing how the tap tone changes as wood is removed from the piece (it gets lower in pitch). I don't believe that the actual frequency will tell you much about the quality of the raw wood itself, which is what I think a lot of folks here seem to be saying. If the pitch changes with mass, shape, and size, how can it tell you anything about the wood itself?
Resonance is different.
In my own work (violin bow making) I have spent an extraordinary amount of time feeling the resonance of the wood when struck. I was taught how to do this by a disgruntled employee of my bow making teacher, William Salchow (Bill wasn't volunteering this information). I think it is essential to getting a great sounding bow.
To feel the vibrations properly you must hold the wood at the nodal point, same way you listen for the tap tone. You find this spot experimentally by moving your hand up and down the stick until you feel the strongest pulsations when tapping the other end.
I have found that two different sticks cut from the same plank can be very different in the power of the vibrations. Some sticks even have two distinct modes of vibration, and they can vibrate in and out of phase and quickly cancel each other out. The ones with the most powerful vibrations with the longest sustain seem to make the best sounding bows, and this sustain seems to be there at all stages of the construction of the bow.
How this might apply to cues I haven't a clue, but I fully intend to continue the practice once I start making them. I seriously doubt that there will be any effect on the actual power of the hit, but I'm thinking it could possibly be a way to help predict which shafts might feel and sound the best for an individual player's preference.
BTW has anyone heard of a device called a "Lucchi meter"? It is an instrument that bow makers use to sort out wood. It measures the longitudinal velocity of the wood vibrations (how fast sound travels from end to end). In theory, the higher the reading, the harder and denser the wood. A lot of top bow makers swear by it. Wish I had one, but they were over $2K that I looked.
