Well, it's not a complete blackout; you can provide the 5-day estimate beforehand, you can send progress reports or two along the way.
The point is, they still are much more comfortable with the demonstration that you are willing to spend as much time as it takes to calm them down in person, progress on the product be damned.
The point is, they still are much more comfortable with the demonstration that you are willing to spend as much time as it takes to calm them down in person, progress on the product be damned.