The problem is, sometimes they work. See https://news.ycombinator.com/item?id=13657508 https://news.ycombinator.com/item?id=13657508. One of the reasons OkCupid

The problem is, sometimes they work. See https://news.ycombinator.com/item?id=13657508 https://news.ycombinator.com/item?id=13657508. One of the reasons OkCupid didn't ban duplicate messages is that often they led to successful exchanges.