Star Trek: Deep Space Nine - Dax Really Isn't Dead!
In the episode "Take Me Out To the Holosuite", the people from DS9 are playing the Vulcans. When Sisko adds the crowd to cheer on Rom in the end, you can clearly see Jadzia Dax in the audience! Isn't she supposed to be dead?
It doesn't matter if Jadzia is in the crowd, it's a HOLOSUITE! She could be a part of the program added by someone. This does not seem like that big a slipup.
It is if you consider the fact that Trills were not known to be on earth during the period which baseball was popular. Add to that the fact that the computer would not arbitrarily put Trill in the audience of a Terran sport. Now if Sisko had specified to mix up races, that's different, but he didn't. The computer would have created a crowd indigenous to the time - namely, Earthers.