It's not about the technical problem, it's about the perception from people of an electronic vote. People that didn't grew up in the tech revolution are going to be skeptical anyway, and I'm not sure about the ones that are full of social induces doubts about everything. It seems to me we are trying to solve a non existant problem
Spot checking isn't enough. To claim that spot checking effectively enforces integrity is turning a blind eye, and shrugging at cut corners.