In my experience it is less about the ears, but more about the habit of basenji's of touching another dog's butt with their mouths slightly opened as an invitation to run/play. Many dogs and their owners don't get this, and react accordingly. I always monitor up close when especially Lela starts interacting with a dog we don't know. Binti is more reserved, so less of an issue with her. See also books by Turid Rugaas: http://en.turid-rugaas.no/