Check this out: http://www.thenewspaper.com/rlc/news.asp?ID=117

At least in Virginia, you apparently have no legal obligation to respond to tickets mailed to you. The article is a little lengthy, but here are some of the pertinent gems...

"There is a practical issue with regard to issuing citations for red light running: the Code of Virginia requires that an in-person summons, rather than certified mail, be used to compel an individual to appear in court. Because of the high cost of delivering summonses outside Virginia, this requirement could make the programs administratively difficult for some localities if it became commonly known that only an in-person summons can require a vehicle owner either to pay the penalty or to appear in court. However, the program can still legally continue in its present form without a change in the Code. Page xii"

and

"The one surviving legal worry actually turns out to be a practical problem, generated by the interaction of the notice provisions in the enabling statute and the Commonwealth

 

http://www.ibiblio.org/rdu/home2.html