This is easy to ensure when the person registered doesn't even exist, but is rather just a figment of a DNC operative's imagination.
Another contributor to vote fraud is "early voting".
Early voting makes it possible for a person to fraudulently vote on behalf of several non-existent people every day during the early-voting period, without interfering with siesta or midnight basketball.
It’s amazing how some people make claims that “thousands” of people can’t possibly muster an ID to vote, and at the same time, that fraud is completely nonexistent. The same folks who claim to represent the “undocumented” couldn’t care less about helping to get them documented and capable of participating more fully in society. They need to be challenged on this.