(contribution sur usenet)
>1. During a referendum, according to the rules, once votes are cast,
>they cannot be changed. What about if someone abstains? Technically
>they are opting to not cast votes at that time. Can that be changed
>later in the referendum to a decisive vote?
(réponse de LSJ)
Abstention is the absence of a vote. It is not a vote to abstain.
You never "decide" to abstain. Abstaining simply describes a vote
(or set of votes) not yet cast. A vote not yet cast can be cast
later.

je pensais qu'il fallait que cela soit dit.