Yep, I'm sure the weather, humidity and so on is important to whether or not the spores colonize but I didn't think of saving them to inoculate plants.
My idea was to develop by selection a race of corn that was genetically more susceptible to infection and letting nature take it's
course. I don't know that it would work and I'm pretty sure it is the exact opposite of what most corn breeders are working toward and actually I select against it myself.
Last year for example I had two plants that produced nice smut near the base of the stalks. I allowed them and the smut to grow but I de-tasseled them so as not to let smut susceptibility cross into my other plants. I left the smut, for the most part, as a test to see if other plants were also susceptible but it did not spread.
I actually have seed from those two plants and I did have the idea that they could be planted as a start on smut producing corn variety. I doubt I will ever follow up with it.