I've heard it said by some chaverim of mine, that if one is to wear tekheles on their tzizits, they should tuck it in. They say many poskim rule this way, and that the gemara brings down something about "doing things out of arrogance", and the gemara brings down someone who wears black shoelaces for the churban beis hamikdash, when at the time wearing black shoelaces wasn't the Minhag. And even though I wear tekheles, I know it's not the minhag for klal yisrael today. Any clarification would be nice.
Rav Hershel Schachter in this shuir at 29:30 says that some are afraid to wear techelis because of mechzei kyuhara,but he explains that is only talking about a middas chassidus not trying to fulfill a positive commandment. Whether one agrees with the idea of wearing techeiles or not if one wants to wear it the idea of mechzei kyuhara should not apply. The shuir itself is on wearing techeiles and Rav Schacters opinon.