Re: Why did Dax remove her spots?
^Agree with above. I think Trills in Starfleet were something of a rarity in Starfleet or the Federation during Kirk's time. Curzon is the only one I know of for sure. Jadzia probably didn't want to arouse suspicion by showing off her spots. Same with Worf. Klingons were around, but one sitting by himself on a Federation space station would have raised too many questions. And no, I don't believe those questions would have had anything to do with his improve make-up and ridges.
"Many things seem clever to an imbecile." --Captain Thelin th'Valrass, USS Enterprise-- "The Chimes at Midnight"