I have played the demo and found that the Curtains in the Decorations section are listed at 0.7 guests/day. Adding curtains to a tavern increase the total guests/day(due to the added prestige, but not directly and it does not increase the Decorations guest/day in the break-down window. So, either the mechanics are wrong or the description is wrong. I do not know what happens in the full version. and you may want to look at that as well.

Edit:
Also, I noticed that When calculating guests/day from prestige the documentation says, " (### * 0.005)," but it appears to really be (### * 0.035).

Edit:
And another thing is the Research guests /day says +1 guest / day while the Guests / day break-down shows research to contribute +7 guests / day.

It would appear as if the original intention of the Guests / day break-down was to show Guests / week and was changed last minute with some items not being changed.