British Airways Gold Guest List members can gift one Gold (Oneworld Emerald) and two Silvers (Oneworld Sapphires) to those on Household Account or Friend & Family list every membership year.
I haven’t paid any attention previously when these gifted statuses have actually expired. I just asked from a friend of mine that signed up for for BA back in July that I gifted BA Silver the other. His status seems to be actually valid for two years.
Here’s what the BA’s FAQ say about this:
Q. If I nominate an existing Executive Club Member to receive a Gold or Silver Executive Club partner card – how long will their tier status be valid for?
A. When you successfully nominate an individual who is already a Member of the Executive Club, their account will be updated immediately and their new tier status will remain valid for the remainder of their current membership year.
Seems that (at least) if you gift the status to a new member it is valid for two years. This certainly would open up opportunities to theoretically “game” the number of family members one could extent the status to.