I think that if the gods call someone, and that someone listens, there is a good chance they will be brought to a teacher or the teacher will be brought to them. If I am supposed to teach, then the students will find me. Hiding will not avoid them, nor will advertising bring them one jot sooner than my Gods have in mind (Iíve tried both, it doesnít matter).
If that goes well, the next step is to invite the prospective student to attend some classes. This does two things, it allows us to see how (and if) they handle homework (yes, there is homework). If we only had one meeting, then it allows the rest of the group to meet the person.
That goes on for a while, and if that goes well, the next step is inviting them to a pre-initiate ritual. We do student rituals on the Full Moons and on the Sabbats. That is we do them when we actually have students. So if we don't have students, someone expresses an interest, then the ritual we have is basically for them. Not a problem in and of itself; if we've allready met them and feel there is a reasonable chance the student/teacher thing can work well, then we are happy to. But we aren't happy if they no-show at the last moment. Especially if they don't even call (or at least e-mail). We are not likely to invite them back. Important point: waiting days to call about missing something and/or "I forgot", "I was drunk/high" and "I didn't think it was important to let you know" as reasons for missing classes or circles translate into "I am a poor fit for this group".
Our pre-initiate rituals are designed to convey some of the same energy as our Gardnerian ones. So if the circle doesn't feel right to the student, that's important - there is no point in going any further because this is not the right place for them. Note that 'feel right' and 'feels strange or uncomfortable' are not mutually exclusive.
We start with the theory, and then go to practical application. This means that pre-initiate (the grounding in principles) and first degree (the application of those principles to Gardnerian specifics) are hard work. Because all students of whatever level are always welcome at classes at any previous level, the more advanced the student, the more possible classes (per week, month or whatever) could be attended. However, any given student chooses their own level of involvment. For Fight Club fans; you choose your level of involvement in project mayhem.
This is 1-a lot of hard work, and 2- not the way most groups choose to train. It's different from the way we were trained. It's interesting for us, we are learning along with our people. Maybe that can serve as insurance against the massive egos that can show up in some parts of the craft. I have learned that I don't have a lot of sympathy for me when I whine about there being too much homework :) That being said, if a student is interested in a more celebratory group, we do know other groups we could hook you up with.
Because we'll be doing it anyway, and if it sounds fun, come and join us. We teach from the material we will be working with, even if we had no students. What offer is to share what we plan on We plan on years of study, lots of books and discussions, research, field trips, rituals. Lots of Craft. Lots of work. No 'official degree', no job, nothing you can put on your resume. Okay, progress far enough, and you could gain Ministerial Credentials. However since it's not that hard to legally form a church (it took us about an hour and a half, and then another morning to register the credentials with the state), that really isn't much incentive. You would have to love it, and be willing to work hard, for reasons that make sense to you; love of the divine, love of the person you would have to become in order to do this.
Oh, another bit of jargon here; the above paragraph could easily be referred to as a scare off speech. At irregular intervals we will tell our students (or those who are considering it) some of the things that this path will require or cause. If that particular something is going to be an issue, or mean that student X would not care to be Gardnerian (or to be accurate, a Gardnerian in our group; as I mentioned above, every group is different) best they learn that as soon as possible. It's the ones that hear that sort of thing and say 'okay, now I want to even more', that are heading in the right direction.
So I guess the short answer to 'why teach all this' is 'why not'. We teach what we have. What we want to get better at.