Most of the radioactive materials pose little threat, especially at the sizes that don't require a license and in the containers those samples are typically sol

Most of the radioactive materials pose little threat, especially at the sizes that don't require a license and in the containers those samples are typically sold in. The only ones that really pose a danger to others is when you have people exceeding the size limit. Most of those people really aren't very knowledgeable, even if they are "deep in the weeds" (Hahn was learning as he went).