So how would you choose which applications to accept?
First come, first served?
So only people around now can be involved in the chapter? That seems like a really bad idea... if you want to keep the chapter running for a long time you need a constant influx of new people.
If there's a limited number of people, then the only real way to do it is for it to be first come first serve - with places becoming available when people leave. Otherwise you end up keeping slots free that you may never use (and turning away useful people). So it's best not to limit it, and if you get a good application, accept it.
Mike