What makes you think random street vendor will be refilling it? Back when you could buy sodas in glass bottles in grocery stores, you could take the empty bott

What makes you think random street vendor will be refilling it? Back when you could buy sodas in glass bottles in grocery stores, you could take the empty bottles (even ones from random street vendor) back to any grocery store, and they'd go back to the bottling plant to be sterilized and refilled. It was very common, and yes, people trusted random street vendors, because the bottles were sealed at the bottling plant. Really, if you are so concerned about random street vendors, you should consider that it is not hard at all to open a plastic soda bottle without breaking the seal ring on the cap, refill the bottle, and put the cap back on.