Reminder: there are many dangers in landscapes and uncapped used syringes is one of them. We encounter this on lower-budget sites and many wild green site margins.
Years ago, one of my managers (ironically the company safety coordinator) worked downtown Vancouver. She reached into a clump of daylilies which was, unfortunately, stuffed full of used needles. She pricked her hand and had to go through a full year of medical testing for HIV and hepatitis. This was distressing both for her and her partner.
Vas Sladek, B.Sc., CLHT