The robot was absolutely free to go around her, I truly don't see how what she did was illegal. The next time my kids are out doing sidewalk chalk and the mail carrier walks by, should the kids be arrested for obstructing mail delivery?
From what I understand, she just stood in front of it. It would be a different thing entirely if she vandalized it in order to obstruct the delivery, but everything in their power is a stretch.
Depends, did they actually block mail delivery and did they do it on purpose in your hypothetical?