I'm currently indexing a magazine, my first indexing effort since the book I did more than a year ago. I remember being confused in my first go-round about whether recipes containing animal rennet-based cheese are categorized as Vegetarian. Given the frequency with which indexers are confronted with this issue, I think it's time for EYB to make the actual policy much more explicit in the indexing instructions.
Currently, the instructions would seem to rule out the Vegetarian category for recipes containg cheese, because most of them are made with animal-derived rennet:
:: If a recipe contains no meat, fish/seafood, poultry, or products of animal slaughter (including meat/fish/poultry stock or broth, anchovies, bacon bits, lard, fish sauce, oyster sauce, Worcestershire sauce, rennet, and gelatin), then list it as Vegetarian in Nutrition. ::
However, it's clear from even a casual glance at recipes categorized as Vegetarian that cheese is not a disqualifier. I seem to recall (but can't locate) a note from Sydney or Deborah on this subject, from my previous indexing reviews, that EYB takes this approach is because the vast majority of users looking for vegetarian recipes would expect cheese to qualify (and that many cheeses available now have non-animal-sourced rennet). That makes a lot of sense, and I don't disagree, but I think that it's important to make that policy and the reasoning for it explicit in the Vegetarian section of the indexing instructions.
The guideline as I understand it is that rennet is a disqualifier for the Vegetarian category only as a specific ingredient of a recipe, and that (potentially or actually rennet-containing) cheese is not -- even specific appellation-controlled cheeses made only with animal-based rennet.