Provide peer review. State clearly if you agree or not. Either way, provide a rebuttal -- support the opposite stance that the original author (even if you didn't originally choose that stance).

When making a plan, as noted in the text, the more accurate information that you have available the better the planning decisions can be made. Planning with just professional planners only is good for targeting what is going to be done, but without operational managers there can be no guarantee that it can actually be done.For planning to happen smoothly there must be a knowledge of operational limitations and capabilities.

Currently I work for a company that maintains US Naval vessels. Our work requires coordination between us and ships force to accomplish repairs and maintenance. The professional planners for the company continually discuss with the Navy ships schedules and movement in order to plan all repairs and maintenance. With supporting 5 vessels and the constant out of town assistance request form other facilities our schedule is full of work that needs to be accomplished. The professional planners plan the events for the company without the knowledge of the workload that the technicians are accomplishing. This can lead to overloading the work schedule or noting a completion date that is unattainable.

Those that should be involved in planning are dependent on what the planning is for. If it is financial planning the CEO, CFO, contracting manager, and general manager. If it is a meeting regarding the operations or growth of the firm than the operations manager should be in attendance as they will and can bring an air of reality to the planning by keeping the firms current capabilities, work load, and workforce size in the minds of the planners.