Or...because it’s not safe! Home-made and other clandestine operation pills can be marked and colored to resemble known medications, but contain very potent other drugs, and in uncontrolled amounts and purities, instead of or in addition to the marked drug. This is one reason the current overdose epidemic is hitting the country’s ER’s and morgues. People think or are told they are buying Methadone or Oxycodone but instead are getting Fentanyl analogs, some of which are hundreds or thousands of times more potent than Morphine.
Like I said, “no packing slip.” Meaning, who could possibly know what the contents were?