Or perhaps I misunderstood, my reading was low humidity matters, but it is quite possible that I know in general for static high humidity shorts everything to ground and so you don't get much static - and thus probably skimmed that part more than I should have.
> This occurred in late summer in South Carolina, August 1980, in extremely high humidity.
But I may have misunderstood this as high humidity being key to it happening, rather than an impediment.