Yeah, the why the hiding behavior is strange. But as anvilheadII said, if they were thrown out with the trash they might be discovered.
One fall morning after the weather had changed I decided to wear a pair of knee high boots and low and behold what was inside but an empty pill bottle, hidden in MY boots. I imagine my ex thought it was a good hiding place in July!!! And the mind erasing pills he was taking, he had no idea where or what he was hiding anymore.