A number of celebrities—including Donald Trump, Howie Mandel and Howard Stern—have a no-handshake policy they insist helps stop the spread of disease. Turns out they’d feel right at home on Crystal, a high-end cruise line that enforces an official handshake ban between passengers and crew. This unfriendly-seeming policy aims to prevent the spread of norovirus, the gastrointestinal bug that has ruined many cruise-goers' vacations of a lifetime (it’s notorious for spreading from human to human in enclosed spaces). Tips for avoiding norovirus include frequent hand washing, not sharing garments or towels, and avoiding oysters and unwashed produce. Do you think this handshake-restriction policy is a smart hygiene move, or sets an unfriendly vibe? Share your thoughts in the comments.