[bunster]

So it is a card that allows you to vote and then you return to desk for next voter — so this person did not return it — does that mean he can vote again or something?

[Uncle Chip]

The card is loaded for one vote —

He could have gone in to vote, was issued a card, changed his mind about voting, and just walked out with the card.

[afraidfortherepublic]

so this person did not return it — does that mean he can vote again or something?

No. Not unless it is re-programmed. If somebody also stole the voter key, they could re-program that card indefinitely.