In real life, if there was a masked vigilante whose codename is ‘Watcher,’ he’s a non-lethal masked vigilante who is a witness to a murder. The detectives and prosecutor want to put the vigilante on the witness stand, but the vigilante’s secret identity is, well, secret, and he doesn’t want to reveal it. Can he still testify with his mask on or testify anonymously?
This actually did happen in Seattle, Washington. There are quite a few real life “super heroes” that dress up and patrol their respective cities. This one was named Phoenix Jones and he had the whole comic book hero costume and everything. There was a law that allowed people to fight as long as both people consented and that played a big into allowing him to do what he did.
But he did end up being pulled into court and they forced him to de-mask himself and reveal his true identity. He even had an “origin story”, though not as dramatic as something like Bruce Wayne, but still. He’s an interesting character to look into.
Consider my comment as just a brief summarization of this whole thing as an answer to your question.