I hear this sentence in the Italian version of Law & Order: Special Victims Unit. I understand I should take it with a little of cum grano salis, and that trying to understand why the plural was used could make little sense, as the translation could have been chosen to be closer to the original sentence in American.
A person, speaking also for other two people, said:
Non vogliamo gli avvocati. Abbiamo deciso di confessare.
In English, the literal translation would be the following. (It's probably not what an American would say.)
We don't want the lawyers. We decided to confess.
I would expect the first sentence to be Non vogliamo l'avvocato. I would not take that to mean there will be a single lawyer representing all three, even if I would not exclude that possibility.
Is using the plural in that sentence the default choice for writing it? Does using the singular give to the sentence a slightly different meaning?