In the movie Eternal sunshine of the spotless mind, there is a mention about the song oh my darling clementine twice. When they first meet, Joel mentions the song to Clementine when she introduces herself. But in their second meeting in the train, Joel has no idea about the song and Clementine sings the song clearly.
Is it that because during the therapy, Joel tried to remember the song in their first meeting and that was caught by the scanner and deleted? Can we assume that this didn't happen during Clementine's therapy and that is why she can remember this song in their second meeting?