We're supposed to business casual, but in reality a few are leaning more on the casual side. But IMO, for a job interview, you should at least be in business casual. Even when I was younger and interviewing for retail work, I was not in a t-shirt and sneakers. I don't know if it's a generational thing or what though.
Hah you say that, but at my old job (where I was the hiring manager), I have had a couple people come with their parents. One time I had a young girl (probably 17 or 18) come to a hiring event with her mom, and it was the mom who spoke and asked questions the whole time. The girl didn't say a word and just stood behind her mom.