It can certainly be proactive once our position has been compromised. We don't need to wait for the opponent to punch us. It is just like paak from the elbow to clear the line when we can't use full range. Also, if our man-sau has lost the line, depending on position, bong+wu should be able to respond to that, as we train in laap-sau drills. But again, it's not contingent upon arm contact or passive in fighting. The stimulus to act is our own bodily awareness of vulnerable position. We should act appropriately before our opponent does, or we will end up further "in the past".
Very well put. Also if our punch (taan concept) is met with our training partner's jum (punch fook sau concept) and he does it well, i.e. the elbow toward our center, we can respond with bong wu to regain the line. This is the yi wei bong sau idea. The opponent's force/direction of force provides the impetus.
How would PB WSL handle someone who just puts their head down and throws uncontrollable and wild hooks? I play this fighting game tekken a lot and a noob can beat me just by mashing all the buttons together and just throwing random stuff everywhere. Reminds me that in a street fight, someone can throw a wild hook which could clip your chin and ko you even if you are more skilled.
Distance control and footwork are the key. Maintain safe distance and let the opponent over extend himself. This is the moment to counter attack.
Fighting is dangerous and nobody is immune to losing..it's a numbers game. Increase the % of success, decrease % of failure. Train skills that can be used automatically under extreme pressure without thinking.