The debut of two brand-new new cruise ships — Cunard's new Queen Elizabeth earlier this month and Royal Caribbean's massive 16-deck Allure of the Seas in December — coincides with the beginning of "wave period," a time of year when most people book their cruise vacations. But talk of cruises inevitably raises the subject of cruise safety. A few weeks ago, a 79-year-old British man disappeared from a cruise ship in the English Channel. He's only the latest in a list of passengers who either vanished or fell overboard. The cruise industry contends a trip on the high seas is safer than a drive to the airport and a stay at a hotel. But just how safe is it? There is little evidence that people are not booking a floating vacation because of safety concerns. But this summer, President Obama signed the Cruise Vessel Security and Safety Act, which requires cruise lines to report all deaths, missing persons, theft, sexual harassment and assaults.