Brilliant thread! One of the most intellectual rational threads I’ve read so far, kudos to all the contributors!!
Now, I would like to add to this conversation and voice my opinion on the subject. The original question: What do we owe the responders?
If we are to adequately answer this question we fist must ask ourselves whether or not pure refined social skills, when used to influence others behaviors, emotions, actions, etc., even in the most subtle of ways, is in fact acceptable/ethical.
Personal ethics are ambiguous, right and wrong can have completely different meanings from one person to the next. So, should we apply our own moral codes to those of others? In my opinion, no. But it happens every day through the legal system. As mentioned earlier in the thread.
There are many parallels between the use of social skills and pheromones, but if we were to restrict pheromones due to ethical concerns then we would have to also to restrict the social aspects as well… Or perhaps, a more reasonable, rather more probable, example would be that if we were to restrict pheromones, would we not then be lead to restrict products which help to enhance natural pheromone production such as vitamins or even celery?
It’s not much of a stretch to assume that such legal action could lead to the demarcation of the most basic of rights, when acting upon ethical codes.
If you have not picked it up by now, I believe that we have no true finite duty to those responders, because ethics are built upon emotion and emotion is a house of cards, hardly suitable for the base of reason. But this is merely my interpretation of such behaviors.. am I right, yes and no. 
The questions are, in this case, more important than answers, because if you give an absolute, there is no question anymore and therefore, no reason for an answer. But hey, some people might see my ethical obscurity as a vice, rather than liberating.
Dominick