There are not enough easily accessible refill faucets at SFO. They could sell cheapo reusable flasks and donate the money to charity.
The flavored water exemption is flat out wrong imo
The goal of this change should be to make an easy positive step not make people worse off because they now can't get their favorite drink when they're already probably stressed at the airport. So I totally understand the exception. I think the next step would be requiring that 'popular' sodas be fountain only.
https://sfoconnect.com/sites/default/files/SFO%20Approved%20...
As you see, it is not about flavored water or brands, it's just about plastic-free container. https://sfoconnect.com/zero-waste-concessions
The second link says "Drinking water includes purified water, mineral water, carbonated or sparkling water, and electrolyte-enhanced water." which isn't extremely specific, but doesn't sound like it includes soda, so it might not include flavored water.