Are you sure they even have access? Does a livestream automatically get archived? Maybe someone can do an experiment with a youtube account, make a livestream and see if it's still available in your channel after you end it. It seems to me that for storage purposes, youtube would probably default to deleting it unless you specifically saved it.
Live stream videos on YouTube are automatically archived and stored to the channel. Unless they intentionally deleted the videos, they should still be there:
When you stream, a public single archive will be generated up to 12 hours. You have the option to check the Make archive private when complete in the Stream Options tab.
The archive will be available in the Video Manager.