If a visitor in someone else's home puts up a mezuza there, and the homeowner will not be home to hang it/make a bracha, does the visitor make the bracha when affixing it? Does it matter whether or not the visitor was appointed a shaliach?
Yalkut Yosef YD 285 Seif 89 says the head of household can appoint a shaliach to affix all the mezuzot. However, the shaliach should make the bracha of "Al Keviat Mezuzah", because whenever a Misvah is done on behalf of someone else, you change it to that form.
I don't see any circumstance where the visitor won't be appointed a shaliach- is he going to sneak into the house and affix Mezuzot?