Ignoring the fact that many of the corner crossing cases were bad faith arguments by landowners intentionally attempting to abuse the situation, I don't think anyone would argue that the park boundary is a prism that extends vertically to infinity.
Why wouldn't it? If you think most people would consider a satellite passing overhead, an airplane flying high overhead, the Moon, the Sun, other objects in space etc. when directly overhead to be "in" a park, I think you'd be mistaken. And the results here bear that out, at least to the limited extent there were relevant questions.
Similarly a subway train passing underneath the park is not "in" the park, nor are vehicles that are at the antipode of the park on the polar opposite side of the Earth.
So where do you draw the line?