Yes, definitely. It's a very populated area, especially at night, especially before NYE. There are tons of people at local bars and restaurants, even well past 2:30 AM. Someone must have seen him leaving or walking alone.
Sorry, I didn't mean that to come off so accusatory and/or rude. I'm not saying she could have or even should have physically stopped him from leaving, but I haven't heard her say that she tried to convince him or plead him to stay, which I guess is understandable because they were in an argument.