[nyolfen]

now this is interesting! what exactly is the rationale used by those who would prefer it remain secret? i assume it's for the preservation of their job or hobby, but i doubt that would fly on its own.

[imron]

A culture of a magician never reveals his secrets.

With the secret unknown it's 'magic'. With the secret known it becomes just a simple trick.

[Tempest1981]

These are essentially trade secrets -- like the recipe for KFC or Coca Cola. Except with the latter, there is plausible denial.