In reply to Flinticus:
Perhaps I should point out that in practice, a well driven stake in decent ground would likely be sound even if the "wrong" way round. The phenomenon I've described was witnessed years ago when we were experimenting with snow stakes. The difference was quite dramatic, enhanced, of course, by the lower frictional properties of snow.
Likewise the "uphill clove-hitch" effect was apparent when playing about with buried ice-axe belays. The hitch is actually unstable in this position, though not insecure, it'll just slide around to its stable position. Again, not likely in practice but I'm surprised that this old chestnut is still doing the rounds.
And if you're putting out videos purporting to show the optimal arrangement, well...