Hi Mr Man,
Thanks for the reminder of that interesting thread about Goenka, IMS, etcviewtopic.php?p=107299#p107299
I guess I would differentiate particular teachers appearing to be isolationist from defining what their practice is. One can find isolationist tendencies in many places...
Ven Analayo comments on these tendencies in this talk at 46:30The Basic Dynamics of Insight Meditation http://www.audiodharma.org/series/208/talk/2749/
This is something I don't understand, why not only advanced meditators, but even meditation teachers, think that what they do is the only right thing, and everybody else is wrong [laughs]. It seems to me like kindergarten: "What I got is better than yours, nyah, nyah!".
Furthermore, most teachers I am familiar with would require some consistency of practice if one wanted to do extended retreats. This is explicitly spelled out in the case of Goenka centres, since they have chosen to have a policy to assure consistency around the world. In other environments, where the local teacher is in sole charge, it would most likely be on a case-by-case basis.