R.I. Gen. Laws § 17-20-33: Disqualification of ballot by board of elections.

The board of elections shall, on its own motion, disqualify any mail ballot which it determines, based upon a preponderance of the evidence, was not voted by the elector who purportedly cast it, or was voted by an elector who was not eligible to vote by mail ballot, or was not obtained and voted in the manner prescribed by this chapter. The board of elections may take this action even in the absence of a challenge to the ballot and may take this action at any time prior to the separation of the ballot from its application and certifying envelope.