I usually don't play at the Venetian, but I played there last month and received a mailer for March. It said the following:
"Bring in this letter and cash your 2008 personal IRS tax refund check at The Venetian or The Palazzo Casino Cage to receive $50 in Slot Credits or Table Match Play! See disclaimer for details."
Disclaimer basically said it must be your own check and NOT valid for direct deposit or corporate refund checks.
GimmeaQuad