Comment from the American Greyhound Track Operators Association:
www.federalreserve.gov/SECRS/2007/November/20071108/R-1298/R-1298_26_1.pdf
It's 11 pages (plus 55 more pages of attachments), but the bottom line is that they are very concerned about overblocking, and they are requesting a definition to the term "unlawful Internet gambling".