Seems that this..
http://www.geni.com/api/project-272/profiles?fields=id,name
Should be limited to primarily the id & name of each profile. However, it gives me a lot more than that.
It gives: url, public first_name, last_name, is_alive, gender, birth date, birth location, death date, death location, burial
If I'm trying to read all the profiles in this project, which is over 5000, most of the traffic is information that I've not requested via the "fields". This is not only a lot of overhead and traffic for you, but for me as well.