About ten years ago, there was a panel of about ten people who made up the judges, from various sex positive backgrounds.
Nominations were received, looked at, then a handful of short-listed nominated people would be asked for more details (this often meant most of the people nominated, because it wasn't huge number for any category). The judges would then have a discussion and, if necessary, a vote.
For some categories - stripping etc - there was a fund-raising performance evening for the judges to see them in action, and we got copies of some of the various films, but escort nominees were never expected to or offered free sessions! Instead, things like work for the community or for particular groups were looked at.
(Based on one year as one of the judges. I think something I did - comment on the high level of sexual harassment at the big ball? - annoyed the person who was ultimately behind it all at the time, and I wasn't invited back for another year.)