Jim Carroll wrote,
"An intelligent musician comes to Ireland to listen to how Irish music is played by the natives, and hopefully take some knowledge away with them.
Unfortunately, what happened to Doolin is the visitors came to play, not to listen."

Jim,

I can see the point you are making, but if I go to a session and I have an instrument with me, I will want to play. That, after all, is the point of a session - at least to me it is.

The point was made in another thread about being sensitive to other participants in a session and I suspect that was what was possibly missing in the case you cited.

As a visitor at a session there are some simple courtesies that can help things along;

1. Ask the existing members of the session before joining in
2. Stay in the background and don't lead a tune unless you are given the nod.
3. If you don't know a tune, don't play, at least initially - though sessions can be good places to learn new tunes.