From the Wichita Eagle:
A Wichita State University mathematician sued the top Kansas election official Wednesday, seeking paper tapes from electronic voting machines in an effort to explain statistical anomalies favoring Republicans in counts coming from large precincts across the country.
(Score: 3, Informative) by mth on Saturday April 25 2015, @10:50AM
A desirable property is if no voter can prove who they voted for. This reduces the ability to bribe or coerce people to vote for a particular party or candidate. That might not be possible if you hand out tokens to be used outside of the polling place. In fact, even if the vote itself could not be traced to the token used after voting, if the token is handed out someone could look over the voter's shoulder as they vote or simply take the token.