[drysart]

But this is very obviously not "no stuff". This is "different stuff".

Taking the website down entirely or just blanking it out is a very, very different matter than replacing it with a different message; and doubly so when the different message is actively harmful to the customer. Unless the designer's contract with the customer explicitly allowed them to do this, this sort of thing is a slam dunk legal case of either vandalism (using a physical metaphor) or in the UK as in this example, a criminal violation of the Computer Misuse Act.

Not to mention that it's an enormous red flag that will scare away other potential customers for this designer; because it demonstrates that you're very willing to sabotage their operations.

[exe34]

it's not the client's website yet, they haven't paid for it!