First let me make clear that I don't own a leo or any sort of gecko, and never have (yet). But my younger one is off and on in love with them, so I've been off & on reading up on them (yes, I know that counts for nothing).
Asides from what Wilomn has already pointed out... this is just one gecko... what I noticed when I looked at the above link is this:
Sounds like calci sand to me? Which everyone seems to agree is bad? So this example doesn't even seem to fit in to the debate about whether or not something like play sand is ok.The intestinal contents contained a sand marketed as "digestable" for reptiles.