[Avodah] CARRYING ON YOM TOV: IS IT ALWAYS PERMITTED?

[Micha Berger via Avodah]

On Sun, Oct 30, 2016 at 03:41:03PM -0400, Akiva Miller via Avodah wrote:
: I don't want any of the things in my house to get stolen, and that's why I
: lock the house when I go to shul. There is a machlokes on whether or not
: this justifies carrying the key on Yom Tov, and the MB says that if I can
: secure those things in some other way, then "all opinions" forbid me to
: carry the key. And that's why I wrote that when I lived in an area without
: an eruv, and people were home to let me in, I saw no heter to carry my key,
: so I used my Shabbos key.

Tangent:
If you don't wear your Shabbos key on yom tov or other times when you
don't need it to avoid hotza'ah, does it still work as a Shabbos key?

Tir'u baTov!
-Micha