In the mid @-@ 2000s , German sect experts expressed concerns that Scientologists were becoming active in the German after @-@ school tutoring market . These concerns arose because customers of around 20 after @-@ school tutoring centres operated by Scientologists in Frankfurt , Hamburg , Stuttgart and elsewhere might be unaware that their children were being taught by Scientologists , using Scientology methods . Brochures advertising the tutoring services would at most mention the name of L. Ron Hubbard , the founder of Scientology , but not Scientology itself .