If it is as they claim nothing but pure water and mint sound like a good idea but I'sure that you can make the same thing yourself for 1/100th of the price you're paying for a pre packaged product by making some mint tea and diluting it. You also assure yourself that the mint is organic. If I'm MCing and hafta be close quaters with other folks I'll make a real strong peppermint tea infusion using several tea bags and carry it in a small bottle and use it to rinse occasionally as mouthwash.
On the freezing, a number of folks have also taken the the frozen lemonade cubes and put them in a blender to make slushies. Also freezing the lemonade in popsicle molds.