Sincere question. Not intended to cause trouble…
There are no doubt times when people enjoy hearing a tune or set that they don’t know, because that’s one way that new tunes are discovered - we hear, and we may ask "what’s the name of that tune; where did it come from?" If we like it, we may learn it. There’s nothing wrong with that, and that’s not what I’m asking about here.
A principal objective of most sessions seems to be to provide an opportunity for multiple people to play tunes together - a joint effort or collaboration that, ideally (IMO) involves as many people as possible. In other words, inclusiveness. Isn’t that why most people would be there? Wouldn’t it be the expectation of most participants that they would be able to participate?
I wonder how many of us would go into a session, and start a tune, or a set of tunes, that we are pretty certain no one else will know. For example, a recent tune written by a friend or acquaintance, or an obscure set that is not available through the usual sources, such as O’Neill’s or the session dot org, and has not been part of the past for that session, unless we were first to ask the group whether they would like to hear it.
I would not do this for what seems to me to be an obvious reason: common courtesy.
Am I being too conventional? Too rigid? Too concerned with involving the session attendees?