Years ago the thing was put on as the National Folk Life Festival under NPS. Since then it has been taken over as a local event. I guess that Cuccinelli's opinion on local parks in Virginia extends to NPS land, or that NPS has the same attitude. (No, seriously, I do not think NPS would try to enforce a new handgun ban at Tredegar just because there was some festival sponsored by a local private group.) A phone call today after the Romney rally may get clarification.
NEED TO WAKE UP AND ENGAGE BRAIN BEFORE POSTING -
The majority of the event appears to take place on private property, with a few events near Tredegar. Other than Tredegatr being open extended hours and offering free admission it seems to have no connection to the event.
Some of the area may in fact be public (City of Richmond) land but then the AG opinion that a private organization can erect/enforce no-firearms rules on public property for the duration of the private organization's event would be the controlling factor.
Somebody needs to have a serious talk with Cooch about that - especially if he wants to be Governor/Senetor/President. He may get there, but that opinion will hopefully haunt him until it is retracted.