Short answer: Not necessarily. Federal rules let Medicare Advantage plans waive the 3-day prior inpatient stay, and many do, but the plan sets the rules, often requires prior authorization, and may charge copayments starting on day 1.
Federal regulation treats a Medicare Advantage enrollee in a plan that offers this benefit as meeting the prior-hospitalization requirement for the SNF stay. Medicare.gov confirms that plans “may also waive” the 3-day minimum and that Advantage members may be charged copayments during the first 20 days, which Original Medicare does not charge.
In Original Medicare the only waiver is through a doctor participating in an Accountable Care Organization approved for the SNF 3-day rule waiver.
For a person comparing a Medigap policy with an Advantage plan, this is a real difference worth checking in the plan’s evidence of coverage: whether the 3-day stay is waived, whether prior authorization is required, and the daily SNF copayment schedule.