> Suppose you find a mushroom that obviously bruises blue and generally matches the phenotype of whatever local psilocybe grows in your area. What's your risk?

If it has chocolate brown spores and bruises blue then the risk is zero in every area that I know of. The only issue people are going to have is not knowing what bluing actually is, and thinking "well maybe this is navy blue" or whatever. Or only looking for bluing on some, but not all of the mushrooms in a collection.