My buddy tried that exact thing last summer. He left his full bottle on the patio table all afternoon, came back to water that was basically soup. He said it was so hot it almost melted the plastic liner inside his bag. Kind of proved your point, I guess, just a little too well.

Projector glare makes fonts vanish too.

Oh man, that's the worst feeling. I've totally been there with a jar of kimchi that basically turned into a bomb. I use the old "two knuckles" rule now, like leave about two finger widths of space at the top. Even then I get nervous and burp it way too often.