itche
“I saw the post about “day beged,” that was what prompted me to start posting in this thread again. My first response to that post was why a tallis katan is a ksus yom. It is a shirt, as evidenced by the fact that many people, Jewish and otherwise wore them as such for centuries and re-enactors still do today. Thus, it is a shirt whether we wear another one on top of it or not. I’m not sure where shatnez comes into it though.”
read some of the other posts on this page. There is a limud from shatnez to tzitzis.
As for the reenactors, i already told you that they are just wearing that garment, with nothing else. So for them, it functions like a shirt. But for us, it has zero function, and it is not even made to have any function (as a ‘day beged’).