I've never seen anyone do it and I wouldn't do it (but I drink water and plain tea...or beer) but I wouldn't have an issue if I saw someone do it. I would probably put it in a baggie (not the original wrapper) so it looks more like a drink supplement (like fibercon or whatever). That way it doesn't look like you are trying to *cheat* the business out of a drink purchase

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Proud to say I haven't shopped at a Wal-Mart since Sept 2003