Vinny was from NY City where suits are if anything more common than in Alabama.
He does know of the necessity to wear a suit to court. He doesn’t for a few reasons:
- He has never been in a real court as a lawyer.
- He underestimated the sophistication of the southerners.
- He underestimated the seriousness of the charges.
- For someone like Vinny, his attire was akin to haute couture for someone of his street background.
According to the script:
(confused) Vinny, you are a criminal attorney, aren't you?
Actually, this will be my first foray into the criminal arena.
(crushed) First time?
(he looks at Bill, then at Vinny) What kind of law do you practice?
Up 'till now, personal injury. (laughs) It just keeps gettin' worse here doesn't it? Got any more questions?
But you are a trial attorney? Personal injury trials?
Actually, this will be my first foray into the trial process - I haven't had to go to court yet - knock on wood.
It does get worse. (beat) You haven't been to court yet, uh, how long have you been practicing?
Six ... weeks ...
(corrects himself) ••• almost six weeks.
STAN looks at Bill, with a hopeless 'what is this?' expression.
But ••• you graduated from law school six years ago, what've you been doing since?
Studying for the bar.
Six years? That's a lotta studying.
(slightly embarrassed) 'To be honest with you, I didn't pass the first time out.
Not only was Vinny not a criminal defense attorney, he had never appeared in front of a judge before, so it is likely he had no idea of any of the procedures, or even expected dress-code. Believable? Not very. However, it is supposed to be a comedy.