No, I would not allow a clean slate just because someone changed their online name. A name change has no bearing on the person actually changing their poor business practices. If someone really wants to start over, they can do that by making amends for past wrongs--changing their name doesn't excuse bad behavior, and it doesn't help the people they've hurt.

Honestly, if I commissioned someone based on what I did or did not see on your site, had trouble with them, found out they were notorious for past trouble under different aliases, and learned that you KNEW that but chose not to disclose it...I would be beyond ticked.