Uh, guys, that thread is a joke. If you bother to read some of the replys, their laughing their asses off at how many other forums that post has shown up on b/c somebody saw it; I guess they get to laugh at us now. Besides, think for half a sec: you gonna suck 13lbs of sand straight into your engine and still have it run? Please; that is the stupidest thing I ever heard.
As for sand and debris accumulating around your filler neck with the potential of getting in your engine when you fill the oil, well, take care of your car. It's common sense to clean the area first. I keep the engine bay as clean as the rest of my car. I really hate it when you see a really nice car and open up the hood to reveal a filthy engine compartment and looks like the owner had never popped the hood in his life