Sure - my point was that it's beneficial to you and the client to have one insulating layer in regards to accounts.

Ideally, you'd want this to be your accounts person.

Yes, but in the non-ideal case, the client is still being deceived.

The general question is: do we have the right to deceive people "for their own good"? I say no.

They are not being deceived. They are being told to pay for the product they received in accordance with the contract terms they agreed to. There is nothing deceptive about a company wanting to be paid for services rendered or products delivered.