I don't think they'd go to this much trouble, the ones I've seen in the stores are juveniles so they aren't even reliably sexable yet at that point. Unfortunately I think it's common for them to sell juveniles because I've spoken to more than one person about how they thought they weren't zebras because they were so much smaller in the store.
It does take some skill to breed out egg scatterers, so it's not like throwing a bunch of guppies in a tank and adding water.
I don't know much about the science behind that, so I have no idea of how a process like that would even work. LFS workers, even at a good lfs, probably wouldn't know first-hand because they aren't likely to successfully spawn in the LFS setting anyhow.
That's a neat article, most of it is greek to me, but looks like it might be the culprit.