Absolutely nothing. I'd assume it was a time of embarrasment for them and they were going through a hard time in their life. The last thing they'd want is a crazy fan or someone laughing at them. Besides their career, they are just like me and you. Humans who feel, think, and breathe. So I'd leave them alone to do their community service just like any other person.
Depends who it was...some I would run over, some I would wave to, some I wouldn't notice, some I would just drive past and others I would commit a crime for so that I could join them.