That, actually, was where it started, and where, philosophically it still rests today. In practise, people now just blow away their original gapps and download

That, actually, was where it started, and where, philosophically it still rests today. In practise, people now just blow away their original gapps and download a separately created gapps package from some free download service and flash it. But in theory, they could have (legally) extracted all the apps from their own phone, saved them, then flashed them back on again themselves. This theoretical possibility is what keeps people using gapps with custom ROMs (just barely) on the legal side of the thin line dividing fair use and outright copyright infringement.