Originally Posted by canadiancow

No. In the past month, I've probably cleared international security for a domestic flight about 5 times.

I've walked domestic to international (airside) about the same number of times.

SFO allows you in any terminal with a boarding pass for any terminal. G and 3 have an unblocked, unmanned, airside connection.

Edit: When I land in 3, I usually walk airside to G and exit over there, because it's easier access to BART. In those situations, I don't even have a departing BP.