To answer the original question, the line of professionalism is drawn by always being aware of the bottom line... it is a student/client-teacher relationship first... and a friendship second. So yes, you can be friendly, meet for a meal, and certainly if you compete together you are going to be spending a considerable amount of time together and getting to know each other quite well. Dancing and competing tend to lend themselves to knowing quite a bit about someone's various personality traits! The bottom line always has to be though... is the teacher delivering quality information, is the student open to learning, and is there a mutually respectful relationship? That is the priority. The friendship.. that is good too if it occurs... but not the priority of the student-teacher relationship.