you sign in each time you start the game. you don't see that because gfwl has auto login enabled by default, which in turn might prevent you from being able to play, as was the case for many people with batman. the "sign in once" thing is how it works on the xbox, not the pc.
it's easy to vilify people disagreeing with you, isn't it.
riiight. so i guess my gg batman copy is illegitimate, just like the serial i received, and same goes for my copy of gta4 on steam.heck, i guess i was being a dirty pirate back when the dow2 mp beta was out and gfwl decided that it wouldn't work for people in networks with standard mtu sizes.
the funniest thing of all is that no gfwl problems actually apply to pirates, since they'll log in using offline profiles anyways, thus pretty much dodging the source of all gfwl related trouble.