Could you explain some of the risks you see? The service is run by the NHS (national health service) and materials are posted back in sealed containers + fixed

Could you explain some of the risks you see? The service is run by the NHS (national health service) and materials are posted back in sealed containers + fixed in a box. The chance of the materials coming into contact with a postman are minuscule. He could jump on the package and it would likely stay in tact.