Illegal voting is "rare" because the system is set up so that it is in most cases impossible to detect.

Can you describe the specific chain of events required to create a fraudulent vote that is "impossible" to detect?

Surely if you can confidently state the system not only is this way, but is purposely designed this way, you should have zero problem describing it exactly step by step.

Extra credit if you can describe a method that can produce 10, 100, or 1000 votes.