My wife runs a natural-ish winery and I help out with some of the regulatory filings. All bottle labels have to be approved by TTB and include the ABV. They don't require you to submit any lab results in support of your claimed alcohol percentage, but if you're caught selling wine outside a certain margin of error it can result in some kind of sanction.
High alcohol wines are somewhat in favor for Napa/Sonoma reds, but 14% is a cutoff for lower excise tax rates and a lesser regulatory burden in general, so it wouldn't be surprising if people are trying to game this somewhat.
A funny thing about wine industry regulation is it's entirely focused on whether or not you are paying taxes. We've never had to file or demonstrate anything related to the safety or purity of our wine.
High alcohol wines are somewhat in favor for Napa/Sonoma reds, but 14% is a cutoff for lower excise tax rates and a lesser regulatory burden in general, so it wouldn't be surprising if people are trying to game this somewhat.
A funny thing about wine industry regulation is it's entirely focused on whether or not you are paying taxes. We've never had to file or demonstrate anything related to the safety or purity of our wine.