Bang Bang/ Surrender Theory
Bang Bang and surrender rules are the same thing just a different name. Within 10ft distance usually or with in a distance or situation that you would not wish to be shot at. I hate the term surrender as it implies that it is voluntary, it is not if used correctly. If used correctly it is obvious to both parties that one person clearly has the advantage while the other one does not and had no chance to provide a response. Surrender/Bang Band to me means that the player choose to tell you they sent a round out to hit you instead of actually shooting you. So in most cases this should be clear and I welcome people choosing not to shoot me in the face in a precarious position and instead letting me know that I am now dead. If it is not absolutely clear that one person has an advantage, then the parlay rules should be utilized. I believe that most grey area incidents could have been avoided if the parlay rule was used.
A Bad Situation
An example of a possible situation that may require a safety kill is if someone is preoccupied climbing down a real steep hill side. The close opposing player should call bang bang/surrender out of safety because of any of the three cases.
1. the climber is not at the ready, not even close to being able to return fire.
2. the climber does not even realize the opposing player is there
3. the climber may fall if he is shot and startled.
Re-Cap of surender/Bang Bang Rules
The "surrenderee" must be in an obvious bad or unprepared position so much that the surrenderee can not have any hope of an adequate response and or their response/reaction may lead them being injured. On the other hand the person calling for surrender or Bang Bang must have a clear and distinct advantage over the surrenderee, usually best described as sneaking up behind the person or has them dead to rights. At the same time a just player can't run around the field at every slight hint of an advantage and be calling for bang bang kills, while the opposing player has a good chance of providing a meaningful response.
Real World Example
But lets face it, that rarely happens, lets take the bush situation for example. In the case described above where 2 people are separated 10ft. by a bush, usually the players are placed into the situation because one player walks into the area where the enemy is already laying in wait. The person laying in wait should either choose to do one of 3 things;
1. Call bang bang, clearly showing they have a good bead and line of sight on the individual while the individual is clearly at a disposition where he could not have provided a meaningful response.
2. Call a parlay and follow parlay rules.
3. Wait for player to move past the minimum engagement distance and shoot with a clear shot.
Conclusion
Most people can't judge distance well and I think that most people get caught up playing the game of airsoft where they are not out unless they are hit by a bb, while some other individuals have the mentality which asks themselves, "if the enemy had a real weapon am I in a decent position to provide a reasonable response or a response at all?" It all boils down to good judgement/common sense and if more people thought the latter, I'm sure there would be less arguing and bickering. In most cases that I have been shot up close, unless I am unjustly lit up with an unnecessary amount of rounds at very close range, I understand that I come out to get shot while playing airsoft! No one wants to be shot by full auto at a close distance, so if in doubt use semi and pick the least sensitive area to shoot.
P.S. I agree with David, these rules don't work well in CQB environments. Instead most bang bang/surrender rules should be placed out the window and put in place semi-auto only and lower FPS rules. At a CQB event it should be expected you are going to get shot up close and personal, just aim for the chest or midsection. And when I say aim, I really mean aim, not just eyeball it. If your gona eyeball it or hip swing it then target the legs cause most people tend to shoot high!