My takeaway from this is that doing something is better than doing nothing, but don't go beyond your means in worrying about it. I have racked to purged keg as my SOP for quite a while, but now I have to consider purging my auto siphon....I recall Charlie Papazian recommending a tube of water to start the siphon - dumping this into an empty pail, then letting the beer flow into your bottles when bottling. Maybe that's another way to go with kegs, too.