The unwritten constitution is the code of ethics that all of our lives are written according to. This is to say that just because there is a code doesn’t mean that you have to follow it in every situation. The best way to think about this is to ask yourself if you would follow this code in any situation.
The best examples I know of this are when it comes to eating and drinking. There is a very specific code of ethics that we are all expected to comply with. For example, when you step out onto a street and you see a person in an alcoholic slumber, you are to hit on them and wake them up so they can get back on it. Yet, if you don’t hit on them, they may never get back on it.