To live life without rules is to invite chaos..
All vendors and venues follow a set of "rules" that determine how they do business. From deadlines to no parking areas, it all comes together for a greater purpose. YOUR SUCCESSFUL EVENT.
For example, let's say your dinner was scheduled to begin at 6:00pm, If the previous event didn't end when they were supposed to, the venue would not have enough time to prepare it for you. Your set up time would be pushed back. It pretty much goes downhill, for all concerned, from there.
Or what if you decided to save some money by hanging some additional items to the lights that the decor company put up. Never mind, the rule that says, any hanging MUST be done by them. An hour into your event the cable comes crashing down, or the power has tripped and you were left in the dark. How about the rule about maximum number of guests and the sewage had had just about enough. you might not see the reasoning behind each rule and find some silly and unnecessary, but a closer look will reveal there is more than just reason, there is experience. Trust the professionals.
How to play by the rules an STILL be in control.