1. Isn't "reyeast"ing only going to work if there's still significant sugar content in the must? If so, then it's just like any other wine company importing/sourcing their fruit, and then adding their yeast in-house. This is VERY common practice. I vint in central california, and if a bottle of wine doesn't explicitly say "estate" on the bottle, they're sourcing their grapes from somewhere off-site (usually still in the same region, but not always. as the label gets larger, the chances increase that you're going out of the region).

2.Oak flakes vs barrels is very obvious if you know what to look for. The rounding out of flavors via microoxygenation is apparent on a bottle that's seen barrel time.

This study was for beginning wine students. Of course they're going to try to pass the test with the information that had just been provided them (red==this, white==that).