Lets say that robot A is trying to hang but robot B is already hanging. Would robot A be allowed to use robot B as a “hanging bar”?
Probably entanglement or something
i was thinking about creating a robot which could pick up an alliance partner as well, but i remember there was a ruling that nullified any points gained.
The definition of both low hanging and high hanging require that the hanging robot be touching the hanging bar. Theoretically you could just lift your partners up to touch the bar but this definitely does add a level of complexity for any teams who were thinking about picking up partners
Entanglement only counts when it’s with the other team.
I’m seeing a flashback: http://www.usfirst.org/uploadedFiles/Community/FRC/FRC_Documents_and_Updates/2007_assets/Manual/0%20-%20Introduction_RevB.pdf
This game had alliance partners lift each other off the ground… 
you only have to touch the hanging bar so technically if you strategically put a tie wrap to touch the bar when hanging from the other robot it would still be legal for both robots.
See the definition of Low Hanging:
They say that one robot is hanging from the other implying that it is off of the tile and therefore the answer is yes this would be considered low hanging if the second robot was touching the bar as well.