Well, not just a test topic, but topics we don’t want to have, we sometimes unlist and those individuals like to use tags for whatever reason, so they’ll put a long list of tags (many that are mis-used).
Yes, this is a rare occurence, but something we notice that was behaving differently than tags used in a private category and unlist and private categories seem to exhibit a lot of the same behavior, they don’t show themselves to normal members. But tags used in those related topics do get shown to normal users.