No, not for the Australians, for her studio audience.
Back in 2004 when Oprah Winfrey gave her entire studio audience brand new cars, the gift turned sour after they found out they'd be stuck with $7,000 in gift taxes. It was a huge PR nightmare, but that's not going to happen with Oprah's gift trip to Australia. Oprah has agreed to pay any fees or taxes associated with her gift. Music to her studio audiences' ears, no doubt. As for the Australian tax payers who are actually paying for the trip, well..uh..yeah.
