According to Billboard:
A Marine Band spokesperson explained to CNN and Washingtonian.com on Tuesday that all music for inaugural ceremonies is recorded as a precaution. “That’s something we’ve done for years and years. The Marine Band did perform live throughout the ceremony but we received last-minute word that Beyoncé wanted to use the recording.”
Band director Colonel Michael J. Colburn told BuzzFeed Shift that Beyoncé didn’t rehearse with the United States Marine Band till the night before the inauguration. “We had Kelly [Clarkson] in over the weekend to rehearse and record. Beyonce, she’s getting ready for the Super Bowl, so we didn’t have a chance to do anything with her until last night so it’s a very, very tight window of opportunity,” he said.