Don't know if anyone's heard this, but it's something to look out for.

So, it's pretty common practice out there for someone breeding a shiny pokemon (either through the RNG method or the tedious Masuda method) to save before the egg hatches, then if the pokemon is shiny, reset. The result is an egg that is known to have a shiny pokemon in it, but since it's an egg, whoever hatches it will be the OT.

Well, apparently when a shiny egg gets traded from DPP to HG/SS, the pokemon that hatches won't be shiny. Several people at other forums have reported having this problem. So, if you're looking do trades involving shiny pokemon, it looks like you'll have to hatch them first.