Originally Posted by wEstSidE
DO ANY OF YOU READ? IT'S NOT A JOB INTERVIEW.
THIS ISN'T YOUR THREAD. MOST OF US WEREN'T TALKING TO YOU.
Most of us were responding to the OP. But since you insist... No matter what they call it, it's a job interview. You will be having lunch with a person from whom you would like a job, and surrounded by other people who also want that job. That's a group job interview. It might be "informal", but you will b judged, and whether you progress to a "formal" interview from here depends on the impression you make at lunch.
Now, consider the following scenarios:
1) You're the only one wearing a suit. The other candidates might resent you, but you will appear to be taking this more seriously than anyone else. Any smart interviewer will see this.
2) Everyone is wearing a suit and so are you. The playing field is level. Time to bring it.
3) You're the only one not wearing a suit. Might as well put your roast beef sandwich in a doggie bag and head home.
Unless you're having lunch at Burger King and you somehow know for a fact that everyone else is going to show up in jeans+t-shirt, you're always better off being over-dressed when interviewing, no matter how informally.