A few years ago, I needed/wanted to drain a full tank of gas from a newish('04) car that I owned.
IIRC, I was finally able to get access to it by removing one of the rear seat cushions, but it wasn't exactly straight forward and wasn't something that could have been done quietly. I'd have been happy to siphon it out of the tank, even if I'd had to let it go all day(provided that I could watch it close enough to swap cans when one got full) but there was no working a hose down the filler neck.
Of course, that's in stark contrast to my MG, where I had a tank phase separate a few years ago and needed to empty the tank. I popped the trunk, disconnected the short flex pipe that ran from the filler neck to the top(filler neck) of the tank itself, then shoved a gasoline rated battery powered pump down in it. I think that was a 10 minute job. That car can be siphoned also-the big leaded filler gives plenty of working room to shove a BIG hose down in it.