RE: backyard archery practice.....gone wrong...
I am sure the law varies from State to State or even by Municipality. I know where I live I have a friend that lives in town and he has been harassed a time or two by a City cop that has seen him shoot, but they have never issued a citation or insisted he stop. They have just tried to make him feel irresponsible even though where he shoots is on a very large lot with a garage as a backdrop which makes it very unlikley that any mishap would ever leave his proprty unless someone purposely did an exargerated "Hail Mary" type shot.
And regardless of how you draw your bow (upwards or downwards) you have to be prepared for an arrow getting away and going high. 33 yards (you said 100') to someone elses backyard does not seem safe even with thick woods between. What if someone walking through woods?
It would seem to me that you need to reposition the direction that you are shooting from so that you have a better backdrop or find another place to shoot. JMO