You're correct about the testing not being a concern. Testing for psilocybin is very expensive and unreliable. Really only one major drug testing lab in the country will even try to test for psilocybin, and that's because you can, for the right price, try to get them to test for just about anything in a mass spec sample. I won't go so far as to say that nobody can ever successfully test you for psilocybin, but it's about as close to never as you can get.