First of all, there is only a hand full of CZTs in the country - around 150. Those individuals have completed the workshop held by Maria Thomas and Rick Roberts, founders of Zentangle.
They have studied the patterns and practices of Zentangle and understand the philosophy behind the art form. There is a big difference between Zentangles and doodles. If you are interested in learning about Zentangles, I highly suggest you take a class from a CZT.