That’s not “exactly” what they mean, as the difference between what you think they’re saying and other commenters think is clearly different. Is la croix or bubbly allowed? If not then what about a hard seltzer? If those are allowed then why isn’t lemon water allowed? If those aren’t allowed then where is the line? Gatorade is seltzer water without the bubbles and with electrolytes. It’s clear that OP’s question was not well thought out, hence why so many people here have a problem with it.