Black Market Wine
Scout & Cellar sells a $25 Gallivant chardonnay. The marketing copy says it's made by "a fifth-generation family winery founded in Monterey in 1883." Sounds legit, but they won't tell you which one.
Wente Vineyards, a fifth-generation family winery founded in 1883 in Monterey just happens to sell an $18 Morning Fog chardonnay.
It's the same wine.

The business of selling bulk wine makes sense. Harvest comes once a year, so if you come up short, you buy bulk to fill gaps. If you get a bumper crop, grapes don't keep. You're better off making wine and selling the excess later. Nothing wrong with that.
What sucks is the deception. Romance sells better than reality, so companies create mystery instead of transparency. Real producers can't shut up about their land. They geek out over soil, elevation, microclimate. The best wineries use transparency as their biggest selling point.
Many brands have realized consumers will trust a story without verifying, so they grift off that expectation. If you notice a winery being vague about where their grapes come from, that's your red flag.
Real wineries love talking about their vineyards.