The passing of time has changed the culture. Everyone wants to know how to get them in the door and to keep them there. I say this doesn't matter. I can't imagine O'Sensei or any other instructor begging students to come in or to stay. Advertising is fine but we should be caterers.
I should also say I do like some of the information that has been provided in this thread as well.
Jigoro Kano used to grab kids on the street and say "Hey, you're pretty big, why don't you ask your mother if you can do Judo?". And that was when Ueshiba was elementary school age!