One of the reasons that I discovered was, because they are new to R/C, their perception is that getting instruction is like going to a school. There would be tests and it would be a slow process before you could get "Certified" as a pilot.
I have found many clubs that require the student demonstrate all kinds of manuvers before they can fly solo. Its a pretty stressfull process for someone who is looking at this hobby as "fun". At my club a new person can fly solo if he/she can demonstrate the following:
1) Controlled takeoff
2) fly the established pattern unassisted (with other R/C aircraft in the air).
3) Controlled Landing on the runways

Once a student has mastered these basics, then the instructors can step back and let them fly solo. If the students asks for additional help we provided it. If the student for some reason begins to to struggle with those basic steps, the instructors will step back in. The instructors are always around to guide them through aerobatics as they become more confident. I think this takes a lot of the stress out of the learning process and the new pilots can relax and just fly, instead of feeling like he/she is being judged or examined all the time while they are just trying to learn.