1)Lack of pressure testing
“Pressure testing” can be defined as conducting a live drill against a fully resisting opponent and getting data as to if/when/where/why/how a particular technique works against a fully resisting opponent.
The instructors who are guilty of this tend to resort to a trope that their system is “too dangerous to go full speed”.
2)Dogmatic Appeals to Authority or Credentials
Just because an instructor taught a demonstration class to a special military unit does not make their system the best one out there.
Just because the instructor may have been part of a special unit, doesn’t make his system the best one out there.
3)Not citing sources or logging development
4)Cattiness Among Communities
Groupthink and its pitfalls can happen anywhere.
5)Pontificating on topics they don’t know enough about
Just because you are an expert in one field, doesn’t make you an expert in another field.