The "full site" setting seems to be stored in a cookie that has a frequent expiry time, and it's unique for every SE site.
Whenever it expires, it is a pain to have to click on the tiny link on the bottom for each SE site you visit (I visit a lot of them) only to have to do the same after a few weeks.
Would it be possible to have a setting in the network profile to force "full site" for all SE sites?