I think the layperson does not realize just how much less impressive it is that the car is not orbiting mars. Inserting a tesla roadster into mars orbit would really have been something challenging. Shooting a big dumb brick off in the general direction of mars is trivial by comparison.
(You shouldn't leave any spirit in direct sunlight, not because the glass containing it may fail--that's definitely weird and not normal--but because it will degrade faster. Cool, dark place is best.)