The trick to this is to remember the exact wording of the law. It is illegal to carry in a place where more than 50% of the sales is from alcohol for consumption on premises as determined by TABC.
This is the real problem. The TABC application asks if for the breakdown of sales by alcohol, food, and other. It does not differentiate between alcohol for on premises or off premises consumption. As a general rule, this is not a problem since most places sell for one or the other. The bars that sell beer for off premises as well as on premises do not sell enough of the off premises to really make a difference. But, with the recent court rulings on wineries and how they can work, the business model they use and the business model TABC uses are not in sync anymore.
So, if the place is a winery and has a store of its own, it can sell for on and off premises consumption and the off premises amount might be enough to make a difference. But the TABC process does not yet allow for the difference and it makes the winery post a 51% sign, even if they would not do so under a stricter interpretation of the actual law.
For right now, this means that sign is legal and you cannot carry there.
The good news is that TABC is aware of this and other problems. They are in the process of completely redesigning the licensing procedures and computer software. I am confident that this is one of the things to be considered. The bad side of this is that I expect it to take about two years for the redesign to be complete and affecting actual licenses and signs. They cannot change the license application until they get the software for the computer redone, and that takes time.