The 1662 Book of Common Prayer of the Church of England (still the official Prayerbook of the Church of England) does not include the double-ring ceremony. In later revisions of that book, all unofficial as Parliament has not ratified any of them) it is still a single-ring ceremony. At the discretion of the parties involved, and with the blessing of the Archbishop of Canterbury, a double-ring ceremony can be performed.
Double-ring ceremonies came out of Protestant Churches in the United States, and are not universally accepted.
In the Russian Orthodox Church, a ring is given (and received) by both parties.
http://www.archive.org/stream/ServiceBookOfHolyOrthodoxChurchByHapgood/Service_Book_Orthodox_Church_Hapgood_djvu.txt
It would appear that Prince William and his wife-to-be are simply following the tradition of the Church of England. Therefore, it is not for us to criticize them.
