Well, you are quite welcome. 
True, but …
By definition, nothing is an excess or deficit unless it is detrimental for the person. There is no need for empirical evidence to support what is true by definition. I think the real question is how one discerns how much is too much or too little at any one moment. And that is one of homosapian’s greater weaknesses. A part of life is the constant effort to keep apprised of such measure concerning one’s ambitions/efforts/intentions.
People are not machines with preset, preprogrammed, precalculated ideal measures of resources (despite modern government efforts to dictate such). How much a person “should” eat for their MIJOT varies each day at least a tiny amount and sometimes a great deal. Such measures cannot be preset without extreme advanced knowledge of each person’s exact individual situation plus extreme knowledge of all aspects of the person (aka “being God” - the ambition of such governments).
If your individual balance of need is already decided for you, then you are not alive. Living is making such decisions for yourself. General guidelines can be provided in advance. Understanding the ideals can be preprogrammed. Probabilities for average situations can be provided for. But to be one among the living, one must carefully attempt to discern the balance, by whatever means he chooses, for himself and be free enough to do so.
General guidelines. I don’t believe that such thoughts can be considered absolute ethics. There are only very few abstract ethics that are absolute.
Again by definition, “greed” is too much. Thus greed is always bad. But bribery is only an offense to a social system and that offense might be a good or bad thing to the person, depending upon more of the situation, especially what type of society. Bribery does not equate to greed, merely flexibility perhaps where it is not authorized. I am sure that wise governances know that mechanisms require grease (that stuff that goes on between the hard rules, aka “under the table”).
The attempt to force all behaviors to be exactly and only by the global rules, is death for both a great many people as well as the government attempting it.
To be “unethical” is to be “anti-social”. Assuming that the bribe in this case was actually anti-social (not merely declared to be by the governance), allowing the bride to function would be unethical. Both parties must contribute their portion of the activity in order for it to function. Either could prevent it. But the one who initiates the action places a greater decision making burden upon the one who must carry it through. He is the “tempter”, so one might think him to be even more guilty. But true life isn’t so simple minded.
If no one ever gets offered a bribe, no one ever gets to instill and reinforce their desire to not take it. They inherently become weaker through atrophy or “lack of practice/conditioning”, being “over-mothered”. Thus being offered a bride on rare occasion actually helps to maintain the lack of it functioning (and this has been experimentally proven, btw, concerning many issues. But don’t ask me for the references).
The sad truth is that the best balance is a little sway. A “little bad” is good if you measure “bad” by preset rules. One must sway in all things enough to maintain the awareness sense of too much and too little and decision making faculties that make up what life is.
Perfection is the seeking of the balance, not being in a prescribed balance. The ideal is being in a state of always adjusting toward the ideal - adjusting toward adjustment toward adjustment … eternally alive. When one stops adjusting because some ideal of perfection has been met, they are dead. Nothing can die until it fails to try. And failing being in the process of trying, is dying - regardless of the cause.
Depends entirely upon the society’s expectations, rules, and needs (and those are very rarely the same).
If life was so simple as to be able to merely state exactly what was good and bad for ALL people, life would have died out very long ago.