From the VDGIF website

"Trespass violations, posting property, and access issues are all concerns affecting landowner's considerations for allowing hunting. Hunters are reminded that it is unlawful to hunt on private property without the permission of the landowner, and hunters must have the permission of the landowner to track or retrieve wounded game on private property."

I clarified this with a conservation officer, and he said that it is certainly against the law to shoot an animal while it is on somone else's property. If somone is setup in a manner that will have them shooting onto your property, then by all means, alert a conservation officer.