At least the person who introduced me told me one should be personally introduced - so I will respect it and leave it at that (it's nothing weird or complicated

At least the person who introduced me told me one should be personally introduced - so I will respect it and leave it at that (it's nothing weird or complicated though and I wouldn't be surprised if rulesets have mutated and forked over time and subgroups). If you are ever in Paris and interested, feel free to reach out :) I didn't actually read the article, but from what I heard the catacombs used to be a lot less safe. I've been told that in the 90s it would be a very bad idea to venture down as one or a small group of women without significant risk for personal safety. Some of the rules definitely come from just being able to preserve the space and experience, but I would guess that some of the social codes also come from enforcing a safer space.