I agree with you both...however I think this is a good metaphor for sensitivity training (Chi-Sao). Especially when it comes to the defensive. Many keep a lot of ego in Chi-Sao play and miss the whole purpose of the flow. Anyone can attack or make something up...how many can truly shut down an attack as its being manifested. This is not done by thinking or seeing...its done by feeling.
The proper training and access to the right info does lay the correct foundation but there is still making it all work. Ive spoken of the Three Families before, Tan, Bong and Fook. All the other 'Sao' are manifestations of the main three. Or should I say somewhere in-between the main three. The basic Phoon Sao structure teaches this.
Just the basics of having wrists properly positioned on the centreline and having forward force will shutdown many attacks before they can even start.
These basics however simple they may seem , have to be worked on for many years until they are perfect.
For most of us mere mortals it means that for a percentage of the time during the rolling cycle one or both of our wrists will not exactly be on the centerline , and we will not have a consistant flow of forward force from both arms during the whole cycle either.
A lot of people will ease off on the forward force rolling from Bong to Tan , allowing their Tan to be collapsed by a strong punch over the top.
Conversely when their Fook sau is in the bottom position the same thing happens , the forward force comes off on their Fook allowing the opponents Tan to strike through.
These errors only have to very minor for someone very skilled in Chi Sau to exploit.
You can get away with not being totally on your game with the inexperienced at Chi sau , because they are so easy to read , before every attack there will be a slight pause or a sudden increase in muscular tension and then the attack will come.
You might not know what , but you know something is coming.
With experienced people there is none of this , the attack just comes without warning or is hidden in the flow of the rolling cycle so you really have to be on the ball and have everything correct.
The best way to develop this ability to not telegraph your intentions in Chi sau is this way .
Stay relaxed and execute your trap or whatever particular attack you are doing
at the same speed you are rolling at.
Roll at a slow speed and
execute your attack at slow speed.
Roll at a medium speed and
execute your attack at medium speed.
Match the speed of the attack with the speed of your rolling.
What this does is eliminates any slight pause or increase in tension that will give the game away and signal to the opponent that you are about to attack
As you get better at this you will be able to roll faster and still stay relaxed and transition seemlessly from the roll and into your attack with out it being detected and you can attack as fast as you want.