Very strange indeed. Mine sits outside during the work week in the boiling sun and I don't have anything like that. I wash weekly with Maguires gold but no water gets up into the hood. Maybe something was left over from manufacturing that you can't see and it melted then dripped out? It could be cosmoline.
I have a VW that leaked an oily gunk out of the back fender well onto my driveway. I figured it was a blown shock that was leaking. Took it to the dealership and they said VW still used cosmoline as a rust preventative on some parts of the chassis. Yep that same yellow-brown waxy goop they used in WWII for firearm preservative is still used in the automotive industry. BTW, it melts between 130-150F. Not sure if its in the new Z's. I've found references of cosmoline being used on older Nissans and Datsuns.