I disagree. Courtesy demand you either answer a yes or no. It is that simple. If someone ask whether your domain name is for sale, don't you think it is appropriate to answer them with a yes or no and also take things up from there?
Hi
I feel what you mean, but you can't be courteous and be demanding, at same time.
also, one assumes that an email, or their email in particular... is not an intrusion or an interruption, from the perspective of the receiver -
the owner of the domain who doesn't anticipate it or may not want it, because they have received so many like it in the past.
and lets not mention those emails from other domains, trying to sell you their fresh hand regs too
but i get some inquires almost every day, either by pm or email and 90% don't make any offers.
they just wanna kick on your tires and see how inflated they are....
or how much air, they suck out of them
majority of people who email you to inquire about a domain already know it's for sale.
yet, some still ask the question.
many don't want to show their hand first.
imo...