HaLeiVi-
The point is that it is the reasonable amount of time to continue to keep it on, similar to quark’s Terutz just without the blanket Hetter.
It’s just that this seems like like a dochek to me being that he put it on specifically for Shabbos. I think it is not reasonable to assume he took it off right away, even if you do give him a little extra time.
quark2-
HaLeiVi now you have me wondering if i was answering anything with that pshat in the first place. Even if it is shev vi’al taaseh, it is still an issur of kilaim.
I had wondered about the same thing but when I checked up the Rambam in Klei Mikdash that I mentioned above I thought it worked out well.
But you can definitely argue and say that a ksus lailah is something that is worn by night, regardless of what kind of beged it really is.
I think that this is the pashtus.
so maybe i wasn’t so far off the mark