I would bust them with the authorities for failing to take their own isolation seriously and by endangering your health by leaving notes and being on your property and porch. You have no idea about the sanitary status of the busybodies nor the notes. I wouldn't touch the notes. Or pick them up with tongs, redeposit them on their own porch, then disinfect the tongs.
There's only one word to describe these folks, and it begins with an "A".
