A mole of CO2 is 44 gm and 22.4 liters at one atmosphere. So, 15 gm is about 1/3 of a mole or 7.6 liters. Squeeze that into a 0.5L bottle and you've got 15.2 volumes.
Those are very strong bottles.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk