One consistent thread throughout Batman canon is that Bruce Wayne, in order to become the legendary crime fighter and world's greatest detective, spent many years of his life training in escape artistry, martial arts, various technological fields related to crime, and [other talents](https://scifi.stackexchange.com/a/21848/20533). 

To learn those skills, particularly martial arts and other hands-on skills, he had to have a teacher of some sort, or at least a partner to go up against. And while he could use a pseudonym, the second he becomes Bruce Wayne again, he's a world-famous figure in the business world. 

How is it that his past trainers and partners haven't recognized this incredibly famous figure who they once taught suspicious crime-fighting skills to?