You have a few objectives:
1. Get to know the consultants, and learn about their experiences
2. Collect advice on how to prepare
3. Have one or more consultant remember you in a positive light
4. Get invited to an interview
Best way to do all of this is to get quality time with the consultants. Early and very late are the times when there are fewer people jockeying for their attention. Obviously be attentive and listen, but also try to bring in an interesting story. I always refer to that applicant who had this story of going to a swamp to count toads as part of his PhD work. Years later, I remember his name (and yes, he got an offer and joined my BCG office).
A networking even will not get you an offer - but hopefully it will help you secure an interview