Gmhdxb to answer you, here are my 2 cents,
as I concluded from the numerous Insead applicants experiences exposed in the forum, the application final study is treated in a roll call process, the shorter the interviews reports are sent to the adcom the first the application is processed and a decision is taken accordingly... So many of us now are already either accepted or dinged or wl.
My side, I had my interviews in July, so according to the theory above my app has been processed and a decision has been taken and the result is listed somewhere on an xls sheet (which I dream to have a look at instead of living this killing wait

). Additionally, as far as I know no one of my recommenders has been called or mailed, I am sure they would have told me if called especially that one of them I is my mger with whom I work every day...
My case says that the interviewers aren't called for each application.
IMO, they could be called only in special cases where the adcom is not able to decide about the app, for ex when there is any confusion or doubt about the rec itself, or when a rec is a short one not giving the minimum needed to let the adcm decide, or when there is a difference between the app and the rec...etc...