score:4
The only thing I can think of in the way of a legal restriction (as opposed to "just don't try it, just don't.") that may catch some tourists by surprise is the banning of bicycles from anywhere but paved roads within Griffith Park. The nicely maintained trails and fire roads might be tempting, but don't do it. The equestrians will do their very best to have you arrested, as they consider it a serious threat to their safety.