Well, if you had people SERIOUSLY studying and adhering to philosophies of other races, I think that would have been more realistic. However, I think Trek really dropped the ball on that because on the rare occasions when we saw a Trek human follow another race's philosophy (Seven, DeSeve, etc.) they were traitors or victims, not people who made a legitimate choice. It's very much a "keep to your own" message--unintended, but I think it's a bad idea.
I would not see a problem with people adopting cultural symbols and the like, but there's VERY much a line that can be crossed. If you had people dressing as Klingons and Vulcans and actually making themselves up to look like those races, that would be bad. VERY bad. (Even in theater acting you'd have a really fine line to be careful of, in the 24th century.)