Yeah, I have the same concerns as divine. I actually knew someone that worked at an agency like that once. She gave me some insight on how they operate. Pretty much everyone passes the auditions because they want to make money from getting people to sign up for the classes. Few that go through all that end up working professionally and those that did succeed probably didn't need the classes to begin with.

You may want to give this a read:

Scams and How to Avoid Them | Acting Studio Chicago

Be careful.