ok so did this actually happen? cuz I wuz lyk(that's right ppls I said lyk and there's nothing you can do about it....this is real defiance ppl!!)watching hetalia and they said that they lyk(said it again!!)did sooo I wuz wondering..............
No they never tried it.
The story changes depending on who is telling the story. There is no hard evidence to prove it that I can find.
One story goes (and I find this to be the most logical (sorta)). The idea was thought of dropping red paint on Mt. Fuji as a form of psychological warfare, however the idea was quickly dismissed because of the pure impracticality of doing it would be.
However you really can't find any evidence other then crackpot stories of "I heard my uncle bob who heard it from his cousin frank, who heard it from his neighbor...." type stories of this.