Why involve ‘strangers’ in strategic planning?

Today I read a challenging question on the email forum of the Future Search Network. A client asked for a Future Search conference for strategic planning for the organisation, an Institute in the health care sector. The Institute’s influential members (the board and the Strategic Planning Committee)  do not want to involve ‘outside stakeholders’. They seem to have great  anxiety about “exposing dirty laundry” or express the belief that “outside stakeholders” have nothing to add to the conversation except  their “opinions”. What should the ...