Ok, I'll call this one. Because most glass is at least semi-transparent, it couldn't heat up more than the surrounding material. I *might* possibly believe you if you claim that bits of clear glass could magnify and focus sunlight on the surrounding vegetation, heating it to the point of ignition (most kids do this experiment with a magnifying glass).
But you're saying that random bits of discarded glass causes more fires in Florida than arson, negligently built campfires, lightning, or drunken fire flies?
Have to agree with that one. Arson and debris from controlled burning are the leaders in causing Florida wildfires. The Pendragon that was once a Florida firefighter (and fought his share of brush fires) suggested that glass could certainly cause a fire - if someone decides to make a Molotov cocktail out of a glass bottle.
Fires aside - at least you don't have to worry as much about someone dropping a rock on your cache in Florida. They aren't exactly plentiful in the woods here!