The Risk of Wing Chun Bong-Sau

[YouKnowWho]

The Wing Chun Bong-Sau is just like the

- XingYi half step Beng Chuan (move leading leg first),
- Bagua circle walking (cross legs),

the safety issue always concern me.

Old Chinese saying said, "拳不露肘(Quan Bu Lu Zhou) - never expose your elbow to your opponent". When you apply the 詠春膀手(Wing Chun Bong-Sau), you expose your elbow joint to your opponent. This will give your opponent a chance to put one hand under your elbow, and another hand on your fore-arm, and rotate your arm into an elbow locking position as shown in the following clip.

http://www.youtube.com/watch?v=vtBljSfkfR8

Do you agree with the principle, "拳不露肘(Quan Bu Lu Zhou) - never expose your elbow to your opponent"? How would you make your Bong-Sau safer to apply if you have to use it?