Is it appropriate to ask Out of Town Guests to bring food?

(Columbia, South Carolina)

A friend invited me and some other friends to come into town for the horse races. Another girl is putting together the event (ie securing the tent for the event) but my friend is hosting me and two other girls.

The person that is putting together the event has contacted each of the out-of -own guest to bring food even though some of us are flying in for the race.

Knowing that my friend was bringing extra people with her, she already promised to bring the tables, table clothes, a meat dish, sides, and desert- as well as 2 types of punch to share.

Though I planned to bring something to be a polite guest, I felt put off by the hostess contacting me asking me to bring additional items. Am I wrong in that it was improper for her to do this? I have hosted her in my house before for an event over a weekend and never asked her to bring items for the event that she participated in. I have responded to her request and am bringing items but wanted to know the proper etiquette in a situation like this. Thanks!