My most memorable consulting misadventure was with a small consulting firm that hired a dozen experienced IT people to work a project that had business acceptance and support, but no MIS support. Most major consulting companies know they must have executive buy-in and an executive sponsor for change initiatives. It is surprising how often they neglect to involve Information Systems Departments. In larger organizations, the Information Systems department wields considerable power and influence that can topple well-intentioned prototypes. If the Information systems department has not been involved from the start, ask yourself why.
Information is withheld.
Assessments and customer interviews can make Information Systems departments and company executives apprehensive. It may be true that customer opinions are critical, but if the customer relationship is a good one, having trusted and qualified people talk to them can only enhance credibility. Recommendations are only as good as the information gathered and the people involved. If you do not provide information to your consultants, the results may be reminiscent of the story of the five blind men describing the elephant. Great business design - but the existing information system causes behavior to revert to old behavioral patterns.