EFI's are a sealed system. My bet is people fill up still because that's what's been taught to them. I doubt it will make one bit of difference to you in the spring when you start it up. Add a bit of stabilizer if it makes you happy.
Remember that blue 92 Ford Flareside I bought (down your way actually) 5 years ago or so... That thing had been sitting for 5 years with a half a tank of gas. Towed it home, added fresh fuel to it and it started right up. After a few seconds of it sorting itself out, you wouldn't have known it hadn't been driven or even started in such a length of time.
http://gtamc.com/showthread.php?1098...worth-it/page4