When I deprime a live primer, I remove the spent primer catchment and the primer fall into an empty cardboard box. I also keep my press clean and ensure flammable materials are not spread all over the place. If a primer was to detonate, it would do so in the metal tube of the press below the shell holder. So I agree with Dillon in the respect, conditions can be present to cause catastrophic results, so the key is to isolate the live primer should it go off.That sounds like the kind of warning that is the result of a really dumb mistake. The kind that should never happen but does.