Everyone knew they existed but since they were seemingly random, and had caused perhaps only a few losses each year, few corporations were willing to invest in counter measures. It became a dead issue until the entire industry got organized and realized that their losses were greater than they knew. Once the money factor was known research into what and where began. So evidence favoring the rogue wave was officially ignored until finance perceived that policy to be against it interest. Perhaps the evidence favoring cold fusion is currently ignored for the same reason.