I have found while working with business groups with limited IT knowledge that it is not sufficient to get signoff of the development project scope by the stakeholders individually. This leads to unexpected misinterpretations and scope creep.
A more effective approach is to gather the stakeholders together and workshop the scope. This gives you the opportunity to respond to any differences of opinion in a forum environment which maximizes the possibility of a common understanding of the scope. In a workshop peer pressure can be used to advantage once consensus has been reached to bring any radical ideas back into line. Remember to record and distribute minutes from the workshop as a future reminder of the scope agreed.